diff --git a/CHANGELOG.en.md b/CHANGELOG.en.md
index 55002e372..47c7ea782 100644
--- a/CHANGELOG.en.md
+++ b/CHANGELOG.en.md
@@ -5,6 +5,18 @@
 
 # Changelog
 
+## Unreleased
+
+- **Confirmation emails for respondents**
+
+    Form owners can enable an automatic confirmation email that is sent to the respondent after a successful submission.
+    Requires an email-validated short text question in the form.
+
+    Supported placeholders in subject/body:
+
+    - `{formTitle}`, `{formDescription}`
+    - `{<fieldName>}` (question `name` or text, sanitized)
+
 ## v5.2.0 - 2025-09-25
 
 - **Time: restrictions and ranges**
diff --git a/docs/API_v3.md b/docs/API_v3.md
index 40c61d54c..888cff84c 100644
--- a/docs/API_v3.md
+++ b/docs/API_v3.md
@@ -175,6 +175,10 @@ Returns the full-depth object of the requested form (without submissions).
   "state": 0,
   "lockedBy": null,
   "lockedUntil": null,
+  "confirmationEmailEnabled": false,
+  "confirmationEmailSubject": null,
+  "confirmationEmailBody": null,
+  "confirmationEmailQuestionId": null,
   "permissions": [
     "edit",
     "results",
diff --git a/docs/DataStructure.md b/docs/DataStructure.md
index a4dc03c64..cdd2f8477 100644
--- a/docs/DataStructure.md
+++ b/docs/DataStructure.md
@@ -13,31 +13,35 @@ This document describes the Object-Structure, that is used within the Forms App
 
 ### Form
 
-| Property             | Type                                 | Restrictions                            | Description                                                                                                                      |
-| -------------------- | ------------------------------------ | --------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
-| id                   | Integer                              | unique                                  | An instance-wide unique id of the form                                                                                           |
-| hash                 | 16-char String                       | unique                                  | An instance-wide unique hash                                                                                                     |
-| title                | String                               | max. 256 ch.                            | The form title                                                                                                                   |
-| description          | String                               | max. 8192 ch.                           | The Form description                                                                                                             |
-| ownerId              | String                               |                                         | The nextcloud userId of the form owner                                                                                           |
-| submissionMessage    | String                               | max. 2048 ch.                           | Optional custom message, with Markdown support, to be shown to users when the form is submitted (default is used if set to null) |
-| created              | unix timestamp                       |                                         | When the form has been created                                                                                                   |
-| access               | [Access-Object](#access-object)      |                                         | Describing access-settings of the form                                                                                           |
-| expires              | unix-timestamp                       |                                         | When the form should expire. Timestamp `0` indicates _never_                                                                     |
-| isAnonymous          | Boolean                              |                                         | If Answers will be stored anonymously                                                                                            |
-| state                | Integer                              | [Form state](#form-state)               | The state of the form                                                                                                            |
-| lockedBy             | String                               |                                         | The user ID for who has exclusive edit access at the moment                                                                      |
-| lockedUntil          | unix timestamp                       |                                         | When the form lock will expire                                                                                                   |
-| submitMultiple       | Boolean                              |                                         | If users are allowed to submit multiple times to the form                                                                        |
-| allowEditSubmissions | Boolean                              |                                         | If users are allowed to edit or delete their response                                                                            |
-| showExpiration       | Boolean                              |                                         | If the expiration date will be shown on the form                                                                                 |
-| canSubmit            | Boolean                              |                                         | If the user can Submit to the form, i.e. calculated information out of `submitMultiple` and existing submissions.                |
-| permissions          | Array of [Permissions](#permissions) | Array of permissions regarding the form |
-| questions            | Array of [Questions](#question)      |                                         | Array of questions belonging to the form                                                                                         |
-| shares               | Array of [Shares](#share)            |                                         | Array of shares of the form                                                                                                      |
-| submissions          | Array of [Submissions](#submission)  |                                         | Array of submissions belonging to the form                                                                                       |
-| submissionCount      | Integer                              |                                         | Number of submissions to the form                                                                                                |
-| submissionMessage    | String                               |                                         | Message to show after a submission                                                                                               |
+| Property                    | Type                                 | Restrictions                            | Description                                                                                                                      |
+| --------------------------- | ------------------------------------ | --------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
+| id                          | Integer                              | unique                                  | An instance-wide unique id of the form                                                                                           |
+| hash                        | 16-char String                       | unique                                  | An instance-wide unique hash                                                                                                     |
+| title                       | String                               | max. 256 ch.                            | The form title                                                                                                                   |
+| description                 | String                               | max. 8192 ch.                           | The Form description                                                                                                             |
+| ownerId                     | String                               |                                         | The nextcloud userId of the form owner                                                                                           |
+| submissionMessage           | String                               | max. 2048 ch.                           | Optional custom message, with Markdown support, to be shown to users when the form is submitted (default is used if set to null) |
+| confirmationEmailEnabled    | Boolean                              |                                         | If enabled, send a confirmation email to the respondent after submission                                                         |
+| confirmationEmailSubject    | String                               | max. 255 ch.                            | Optional confirmation email subject template (supports placeholders)                                                             |
+| confirmationEmailBody       | String                               |                                         | Optional confirmation email body template (plain text, supports placeholders)                                                    |
+| confirmationEmailQuestionId | Integer                              |                                         | The id of the question belonging to the form, that holds the email address of the respondent                                     |
+| created                     | unix timestamp                       |                                         | When the form has been created                                                                                                   |
+| access                      | [Access-Object](#access-object)      |                                         | Describing access-settings of the form                                                                                           |
+| expires                     | unix-timestamp                       |                                         | When the form should expire. Timestamp `0` indicates _never_                                                                     |
+| isAnonymous                 | Boolean                              |                                         | If Answers will be stored anonymously                                                                                            |
+| state                       | Integer                              | [Form state](#form-state)               | The state of the form                                                                                                            |
+| lockedBy                    | String                               |                                         | The user ID for who has exclusive edit access at the moment                                                                      |
+| lockedUntil                 | unix timestamp                       |                                         | When the form lock will expire                                                                                                   |
+| submitMultiple              | Boolean                              |                                         | If users are allowed to submit multiple times to the form                                                                        |
+| allowEditSubmissions        | Boolean                              |                                         | If users are allowed to edit or delete their response                                                                            |
+| showExpiration              | Boolean                              |                                         | If the expiration date will be shown on the form                                                                                 |
+| canSubmit                   | Boolean                              |                                         | If the user can Submit to the form, i.e. calculated information out of `submitMultiple` and existing submissions.                |
+| permissions                 | Array of [Permissions](#permissions) | Array of permissions regarding the form |
+| questions                   | Array of [Questions](#question)      |                                         | Array of questions belonging to the form                                                                                         |
+| shares                      | Array of [Shares](#share)            |                                         | Array of shares of the form                                                                                                      |
+| submissions                 | Array of [Submissions](#submission)  |                                         | Array of submissions belonging to the form                                                                                       |
+| submissionCount             | Integer                              |                                         | Number of submissions to the form                                                                                                |
+| submissionMessage           | String                               |                                         | Message to show after a submission                                                                                               |
 
 ```
 {
@@ -46,6 +50,10 @@ This document describes the Object-Structure, that is used within the Forms App
   "title": "Form 1",
   "description": "Description Text",
   "ownerId": "jonas",
+  "confirmationEmailEnabled": false,
+  "confirmationEmailSubject": null,
+  "confirmationEmailBody": null,
+  "confirmationEmailQuestionId": null,
   "created": 1611240961,
   "access": {},
   "expires": 0,
diff --git a/lib/BackgroundJob/SendConfirmationMailJob.php b/lib/BackgroundJob/SendConfirmationMailJob.php
new file mode 100644
index 000000000..c6db53c94
--- /dev/null
+++ b/lib/BackgroundJob/SendConfirmationMailJob.php
@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Forms\BackgroundJob;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\QueuedJob;
+use OCP\Defaults;
+use OCP\Mail\IMailer;
+use OCP\Util;
+use Psr\Log\LoggerInterface;
+
+class SendConfirmationMailJob extends QueuedJob {
+	public function __construct(
+		ITimeFactory $time,
+		private IMailer $mailer,
+		private LoggerInterface $logger,
+		private Defaults $defaults,
+	) {
+		parent::__construct($time);
+	}
+
+	/**
+	 * @param array{recipient: string, subject: string, body: string, formId: int, submissionId: int} $argument
+	 */
+	public function run($argument): void {
+		$recipient = $argument['recipient'];
+		$subject = $argument['subject'];
+		$body = $argument['body'];
+		$formId = $argument['formId'];
+		$submissionId = $argument['submissionId'];
+
+		try {
+			$emailTemplate = $this->mailer->createEMailTemplate('forms.Confirmation');
+			$emailTemplate->setSubject($subject);
+			$emailTemplate->addHeader();
+			$emailTemplate->addHeading($subject);
+			$emailTemplate->addBodyText($body);
+			$emailTemplate->addFooter();
+
+			$message = $this->mailer->createMessage();
+			$message->setFrom([Util::getDefaultEmailAddress('noreply') => $this->defaults->getName()]);
+			$message->setTo([$recipient]);
+			$message->useTemplate($emailTemplate);
+			$this->mailer->send($message);
+			$this->logger->debug('Confirmation email sent successfully', [
+				'formId' => $formId,
+				'submissionId' => $submissionId,
+			]);
+		} catch (\Exception $e) {
+			$this->logger->error('Error while sending confirmation email', [
+				'exception' => $e,
+				'formId' => $formId,
+				'submissionId' => $submissionId,
+			]);
+		}
+	}
+}
diff --git a/lib/Constants.php b/lib/Constants.php
index 0ff0341bd..fa0c347db 100644
--- a/lib/Constants.php
+++ b/lib/Constants.php
@@ -18,12 +18,16 @@ class Constants {
 	public const CONFIG_KEY_ALLOWSHOWTOALL = 'allowShowToAll';
 	public const CONFIG_KEY_CREATIONALLOWEDGROUPS = 'creationAllowedGroups';
 	public const CONFIG_KEY_RESTRICTCREATION = 'restrictCreation';
+	public const CONFIG_KEY_ALLOWCONFIRMATIONEMAIL = 'allowConfirmationEmail';
+	public const CONFIG_KEY_CONFIRMATIONEMAILRATELIMIT = 'confirmationEmailRateLimit';
 	public const CONFIG_KEYS = [
 		self::CONFIG_KEY_ALLOWPERMITALL,
 		self::CONFIG_KEY_ALLOWPUBLICLINK,
 		self::CONFIG_KEY_ALLOWSHOWTOALL,
 		self::CONFIG_KEY_CREATIONALLOWEDGROUPS,
-		self::CONFIG_KEY_RESTRICTCREATION
+		self::CONFIG_KEY_RESTRICTCREATION,
+		self::CONFIG_KEY_ALLOWCONFIRMATIONEMAIL,
+		self::CONFIG_KEY_CONFIRMATIONEMAILRATELIMIT,
 	];
 
 	/**
@@ -33,6 +37,8 @@ class Constants {
 		'formTitle' => 256,
 		'formDescription' => 8192,
 		'submissionMessage' => 2048,
+		'confirmationEmailSubject' => 255,
+		'confirmationEmailBody' => 8192,
 		'questionText' => 2048,
 		'questionDescription' => 4096,
 		'optionText' => 1024,
diff --git a/lib/Controller/ApiController.php b/lib/Controller/ApiController.php
index feca1a12f..dbb998e88 100644
--- a/lib/Controller/ApiController.php
+++ b/lib/Controller/ApiController.php
@@ -25,6 +25,7 @@
 use OCA\Forms\Exception\NoSuchFormException;
 use OCA\Forms\ResponseDefinitions;
 use OCA\Forms\Service\ConfigService;
+use OCA\Forms\Service\ConfirmationEmailService;
 use OCA\Forms\Service\FormsService;
 use OCA\Forms\Service\SubmissionService;
 
@@ -80,6 +81,7 @@ public function __construct(
 		private QuestionMapper $questionMapper,
 		private ShareMapper $shareMapper,
 		private SubmissionMapper $submissionMapper,
+		private ConfirmationEmailService $confirmationEmailService,
 		private ConfigService $configService,
 		private FormsService $formsService,
 		private SubmissionService $submissionService,
@@ -206,12 +208,15 @@ public function newForm(?int $fromId = null): DataResponse {
 			$formData['showExpiration'] = false;
 			$formData['expires'] = 0;
 			$formData['isAnonymous'] = false;
+			unset($formData['confirmationEmailQuestionId']);
 
 			$form = Form::fromParams($formData);
 			$this->formMapper->insert($form);
 
 			// Get Questions, set new formId, reinsert
 			$questions = $this->questionMapper->findByForm($oldForm->getId());
+			$oldConfirmationEmailQuestionId = $oldForm->getConfirmationEmailQuestionId();
+
 			foreach ($questions as $oldQuestion) {
 				$questionData = $oldQuestion->read();
 
@@ -220,6 +225,10 @@ public function newForm(?int $fromId = null): DataResponse {
 				$newQuestion = Question::fromParams($questionData);
 				$this->questionMapper->insert($newQuestion);
 
+				if (isset($oldConfirmationEmailQuestionId) && $oldConfirmationEmailQuestionId === $oldQuestion->getId()) {
+					$form->setConfirmationEmailQuestionId($newQuestion->getId());
+				}
+
 				// Get Options, set new QuestionId, reinsert
 				$options = $this->optionMapper->findByQuestion($oldQuestion->getId());
 				foreach ($options as $oldOption) {
@@ -231,6 +240,8 @@ public function newForm(?int $fromId = null): DataResponse {
 					$this->optionMapper->insert($newOption);
 				}
 			}
+
+			$this->formMapper->update($form);
 		}
 
 		return new DataResponse($this->formsService->getForm($form), Http::STATUS_CREATED);
@@ -333,6 +344,22 @@ public function updateForm(int $formId, array $keyValuePairs): DataResponse {
 		unset($keyValuePairs['fileId']);
 		unset($keyValuePairs['fileFormat']);
 
+		if (array_key_exists('confirmationEmailQuestionId', $keyValuePairs)) {
+			try {
+				$this->confirmationEmailService->validateRecipientQuestionId($form, $keyValuePairs['confirmationEmailQuestionId']);
+			} catch (\InvalidArgumentException $e) {
+				throw new OCSBadRequestException('Invalid confirmationEmailQuestionId, will not update.');
+			}
+		}
+
+		foreach (['confirmationEmailSubject', 'confirmationEmailBody'] as $field) {
+			if (array_key_exists($field, $keyValuePairs)
+				&& is_string($keyValuePairs[$field])
+				&& mb_strlen($keyValuePairs[$field]) > Constants::MAX_STRING_LENGTHS[$field]) {
+				throw new OCSBadRequestException($field . ' exceeds maximum length of ' . Constants::MAX_STRING_LENGTHS[$field] . ' characters.');
+			}
+		}
+
 		// Create FormEntity with given Params & Id.
 		foreach ($keyValuePairs as $key => $value) {
 			$method = 'set' . ucfirst($key);
@@ -649,6 +676,11 @@ public function updateQuestion(int $formId, int $questionId, array $keyValuePair
 			throw new OCSBadRequestException('Invalid extraSettings, will not update.');
 		}
 
+		if ($form->getConfirmationEmailQuestionId() === $question->getId()
+			&& !$question->isEmailType($keyValuePairs['type'] ?? null, $keyValuePairs['extraSettings'] ?? null)) {
+			$form->setConfirmationEmailQuestionId(null);
+		}
+
 		// Create QuestionEntity with given Params & Id.
 		$question = Question::fromParams($keyValuePairs);
 		$question->setId($questionId);
@@ -720,6 +752,10 @@ public function deleteQuestion(int $formId, int $questionId): DataResponse {
 			}
 		}
 
+		if ($form->getConfirmationEmailQuestionId() === $questionId) {
+			$form->setConfirmationEmailQuestionId(null);
+		}
+
 		$this->formMapper->update($form);
 
 		return new DataResponse($questionId);
diff --git a/lib/Db/Form.php b/lib/Db/Form.php
index d3c9999df..fe035cfe1 100644
--- a/lib/Db/Form.php
+++ b/lib/Db/Form.php
@@ -53,6 +53,14 @@
  * @method int|null getMaxSubmissions()
  * @method void setMaxSubmissions(int|null $value)
  * @method void setLockedUntil(int|null $value)
+ * @method bool getConfirmationEmailEnabled()
+ * @method void setConfirmationEmailEnabled(bool $value)
+ * @method string|null getConfirmationEmailSubject()
+ * @method void setConfirmationEmailSubject(string|null $value)
+ * @method string|null getConfirmationEmailBody()
+ * @method void setConfirmationEmailBody(string|null $value)
+ * @method int|null getConfirmationEmailQuestionId()
+ * @method void setConfirmationEmailQuestionId(int|null $value)
  */
 class Form extends Entity {
 	protected $hash;
@@ -74,6 +82,10 @@ class Form extends Entity {
 	protected $lockedBy;
 	protected $lockedUntil;
 	protected $maxSubmissions;
+	protected $confirmationEmailEnabled;
+	protected $confirmationEmailSubject;
+	protected $confirmationEmailBody;
+	protected $confirmationEmailQuestionId;
 
 	/**
 	 * Form constructor.
@@ -90,6 +102,8 @@ public function __construct() {
 		$this->addType('lockedBy', 'string');
 		$this->addType('lockedUntil', 'integer');
 		$this->addType('maxSubmissions', 'integer');
+		$this->addType('confirmationEmailEnabled', 'boolean');
+		$this->addType('confirmationEmailQuestionId', 'integer');
 	}
 
 	// JSON-Decoding of access-column.
@@ -164,6 +178,10 @@ public function setAccess(array $access): void {
 	 *   lockedBy: ?string,
 	 *   lockedUntil: ?int,
 	 *   maxSubmissions: ?int,
+	 *   confirmationEmailEnabled: bool,
+	 *   confirmationEmailSubject: ?string,
+	 *   confirmationEmailBody: ?string,
+	 *   confirmationEmailQuestionId: ?int,
 	 *  }
 	 */
 	public function read() {
@@ -188,6 +206,10 @@ public function read() {
 			'lockedBy' => $this->getLockedBy(),
 			'lockedUntil' => $this->getLockedUntil(),
 			'maxSubmissions' => $this->getMaxSubmissions(),
+			'confirmationEmailEnabled' => (bool)$this->getConfirmationEmailEnabled(),
+			'confirmationEmailSubject' => $this->getConfirmationEmailSubject(),
+			'confirmationEmailBody' => $this->getConfirmationEmailBody(),
+			'confirmationEmailQuestionId' => $this->getConfirmationEmailQuestionId(),
 		];
 	}
 }
diff --git a/lib/Db/Question.php b/lib/Db/Question.php
index e5e226cf8..05355b95f 100644
--- a/lib/Db/Question.php
+++ b/lib/Db/Question.php
@@ -100,4 +100,19 @@ public function read(): array {
 			'extraSettings' => $this->getExtraSettings(),
 		];
 	}
+
+	/**
+	 * Check if the question is a short text question with email validation.
+	 */
+	public function isEmailType(?string $type = null, ?array $extraSettings = null): bool {
+		return self::checkEmailType(
+			$type ?? $this->getType(),
+			$extraSettings ?? $this->getExtraSettings()
+		);
+	}
+
+	public static function checkEmailType(string $type, array $extraSettings): bool {
+		return $type === \OCA\Forms\Constants::ANSWER_TYPE_SHORT
+			&& ($extraSettings['validationType'] ?? null) === 'email';
+	}
 }
diff --git a/lib/FormsMigrator.php b/lib/FormsMigrator.php
index 5a74db027..e21f25701 100644
--- a/lib/FormsMigrator.php
+++ b/lib/FormsMigrator.php
@@ -149,6 +149,10 @@ public function import(IUser $user, IImportSource $importSource, OutputInterface
 				$form->setAllowEditSubmissions($formData['allowEditSubmissions']);
 				$form->setShowExpiration($formData['showExpiration']);
 				$form->setMaxSubmissions($formData['maxSubmissions'] ?? null);
+				$form->setConfirmationEmailEnabled($formData['confirmationEmailEnabled'] ?? false);
+				$form->setConfirmationEmailSubject($formData['confirmationEmailSubject'] ?? null);
+				$form->setConfirmationEmailBody($formData['confirmationEmailBody'] ?? null);
+				$form->setConfirmationEmailQuestionId(null); // Set to null initially, updated after questions are imported
 
 				$this->formMapper->insert($form);
 
@@ -177,6 +181,12 @@ public function import(IUser $user, IImportSource $importSource, OutputInterface
 					}
 				}
 
+				if (($formData['confirmationEmailQuestionId'] ?? null) !== null
+					&& isset($questionIdMap[$formData['confirmationEmailQuestionId']])) {
+					$form->setConfirmationEmailQuestionId($questionIdMap[$formData['confirmationEmailQuestionId']]);
+					$this->formMapper->update($form);
+				}
+
 				foreach ($formData['submissions'] as $submissionData) {
 					$submission = new Submission();
 					$submission->setFormId($form->getId());
diff --git a/lib/Migration/Version050300Date20260413233000.php b/lib/Migration/Version050300Date20260413233000.php
new file mode 100644
index 000000000..6e3cd34b5
--- /dev/null
+++ b/lib/Migration/Version050300Date20260413233000.php
@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Forms\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Add confirmation email fields to forms
+ */
+class Version050300Date20260413233000 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+		$table = $schema->getTable('forms_v2_forms');
+		$changed = false;
+
+		if (!$table->hasColumn('confirmation_email_enabled')) {
+			$table->addColumn('confirmation_email_enabled', Types::BOOLEAN, [
+				'notnull' => false,
+				'default' => 0,
+			]);
+			$changed = true;
+		}
+
+		if (!$table->hasColumn('confirmation_email_subject')) {
+			$table->addColumn('confirmation_email_subject', Types::STRING, [
+				'notnull' => false,
+				'default' => null,
+				'length' => 255,
+			]);
+			$changed = true;
+		}
+
+		if (!$table->hasColumn('confirmation_email_body')) {
+			$table->addColumn('confirmation_email_body', Types::TEXT, [
+				'notnull' => false,
+				'default' => null,
+			]);
+			$changed = true;
+		}
+
+		if (!$table->hasColumn('confirmation_email_question_id')) {
+			$table->addColumn('confirmation_email_question_id', Types::INTEGER, [
+				'notnull' => false,
+				'default' => null,
+			]);
+			$changed = true;
+		}
+
+		return $changed ? $schema : null;
+	}
+}
diff --git a/lib/ResponseDefinitions.php b/lib/ResponseDefinitions.php
index 27fea25bb..e71b0e51b 100644
--- a/lib/ResponseDefinitions.php
+++ b/lib/ResponseDefinitions.php
@@ -141,6 +141,10 @@
  *   shares: list<FormsShare>,
  *   submissionCount?: int,
  *   submissionMessage: ?string,
+ *   confirmationEmailEnabled: bool,
+ *   confirmationEmailSubject: ?string,
+ *   confirmationEmailBody: ?string,
+ *   confirmationEmailQuestionId: ?int,
  * }
  *
  * @psalm-type FormsUploadedFile = array{
diff --git a/lib/Service/ConfigService.php b/lib/Service/ConfigService.php
index 593315c9e..6632bf810 100644
--- a/lib/Service/ConfigService.php
+++ b/lib/Service/ConfigService.php
@@ -10,6 +10,7 @@
 
 use OCA\Forms\Constants;
 
+use OCP\AppFramework\Services\IAppConfig;
 use OCP\IConfig;
 use OCP\IGroup;
 use OCP\IGroupManager;
@@ -22,6 +23,7 @@ class ConfigService {
 	public function __construct(
 		protected string $appName,
 		private IConfig $config,
+		private IAppConfig $appConfig,
 		private IGroupManager $groupManager,
 		IUserSession $userSession,
 	) {
@@ -50,6 +52,14 @@ public function getRestrictCreation(): bool {
 		return json_decode($this->config->getAppValue($this->appName, Constants::CONFIG_KEY_RESTRICTCREATION, 'false'));
 	}
 
+	public function getAllowConfirmationEmail(): bool {
+		return $this->appConfig->getAppValueBool(Constants::CONFIG_KEY_ALLOWCONFIRMATIONEMAIL, false);
+	}
+
+	public function getConfirmationEmailRateLimit(): int {
+		return $this->appConfig->getAppValueInt(Constants::CONFIG_KEY_CONFIRMATIONEMAILRATELIMIT, 3);
+	}
+
 	/**
 	 * Provide the full AppConfig
 	 */
@@ -60,6 +70,8 @@ public function getAppConfig(): array {
 			Constants::CONFIG_KEY_ALLOWSHOWTOALL => $this->getAllowShowToAll(),
 			Constants::CONFIG_KEY_CREATIONALLOWEDGROUPS => $this->getCreationAllowedGroups(),
 			Constants::CONFIG_KEY_RESTRICTCREATION => $this->getRestrictCreation(),
+			Constants::CONFIG_KEY_ALLOWCONFIRMATIONEMAIL => $this->getAllowConfirmationEmail(),
+			Constants::CONFIG_KEY_CONFIRMATIONEMAILRATELIMIT => $this->getConfirmationEmailRateLimit(),
 
 			// Additional, calculated information out of Config
 			'canCreateForms' => $this->canCreateForms()
diff --git a/lib/Service/ConfirmationEmailService.php b/lib/Service/ConfirmationEmailService.php
new file mode 100644
index 000000000..3032a23dd
--- /dev/null
+++ b/lib/Service/ConfirmationEmailService.php
@@ -0,0 +1,263 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Forms\Service;
+
+use OCA\Forms\BackgroundJob\SendConfirmationMailJob;
+use OCA\Forms\Db\AnswerMapper;
+use OCA\Forms\Db\Form;
+use OCA\Forms\Db\Question;
+use OCA\Forms\Db\QuestionMapper;
+use OCA\Forms\Db\Submission;
+use OCP\AppFramework\Db\IMapperException;
+use OCP\BackgroundJob\IJobList;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IL10N;
+use OCP\IMemcache;
+use OCP\Mail\IEmailValidator;
+use Psr\Log\LoggerInterface;
+
+class ConfirmationEmailService {
+	private const RATE_LIMIT_TTL = 86400; // 24 hours
+
+	private ICache $rateLimitCache;
+
+	public function __construct(
+		private ConfigService $configService,
+		private AnswerMapper $answerMapper,
+		private QuestionMapper $questionMapper,
+		private IEmailValidator $emailValidator,
+		private IJobList $jobList,
+		ICacheFactory $cacheFactory,
+		private IL10N $l10n,
+		private LoggerInterface $logger,
+	) {
+		$this->rateLimitCache = $cacheFactory->createDistributed('forms_confirmation_email');
+	}
+
+	public function send(Form $form, Submission $submission): void {
+		if (!$form->getConfirmationEmailEnabled()) {
+			return;
+		}
+
+		if (!$this->configService->getAllowConfirmationEmail()) {
+			$this->logger->debug('Confirmation email feature is disabled by administrator', [
+				'formId' => $form->getId(),
+			]);
+			return;
+		}
+
+		$questions = $this->loadQuestions($form->getId());
+		$answerMap = $this->buildAnswerMap($submission);
+
+		$recipientQuestion = $this->findRecipientQuestion($form, $questions);
+		if ($recipientQuestion === null) {
+			if ($form->getConfirmationEmailQuestionId() !== null) {
+				$this->logger->debug('Configured confirmation email recipient question is not a valid email question', [
+					'formId' => $form->getId(),
+					'submissionId' => $submission->getId(),
+					'configuredQuestionId' => $form->getConfirmationEmailQuestionId(),
+				]);
+			}
+			return;
+		}
+
+		$recipientEmail = $answerMap[$recipientQuestion['id']][0] ?? null;
+		if ($recipientEmail === null || !$this->emailValidator->isValid($recipientEmail)) {
+			$this->logger->debug('No valid email address found in submission for confirmation email', [
+				'formId' => $form->getId(),
+				'submissionId' => $submission->getId(),
+			]);
+			return;
+		}
+
+		if (!$this->checkRateLimit($recipientEmail, $form->getId(), $submission->getId())) {
+			return;
+		}
+
+		[$subject, $body] = $this->buildEmailContent($form, $questions, $answerMap);
+
+		$this->jobList->add(SendConfirmationMailJob::class, [
+			'recipient' => $recipientEmail,
+			'subject' => $subject,
+			'body' => $body,
+			'formId' => $form->getId(),
+			'submissionId' => $submission->getId(),
+		]);
+		$this->logger->debug('Confirmation email queued', [
+			'formId' => $form->getId(),
+			'submissionId' => $submission->getId(),
+		]);
+	}
+
+	/**
+	 * @throws \InvalidArgumentException
+	 */
+	public function validateRecipientQuestionId(Form $form, mixed $recipientId): void {
+		if ($recipientId === null) {
+			return;
+		}
+
+		if (!is_int($recipientId)) {
+			throw new \InvalidArgumentException('Invalid confirmationEmailQuestionId');
+		}
+
+		try {
+			$question = $this->questionMapper->findById($recipientId);
+		} catch (IMapperException $e) {
+			throw new \InvalidArgumentException('Invalid confirmationEmailQuestionId', previous: $e);
+		}
+
+		if ($question->getFormId() !== $form->getId()
+			|| $question->getOrder() === 0
+			|| !$question->isEmailType()) {
+			throw new \InvalidArgumentException('Invalid confirmationEmailQuestionId');
+		}
+	}
+
+	/**
+	 * Load questions for a form. Skips options and file-type processing not needed for email.
+	 *
+	 * @return list<array<string, mixed>>
+	 */
+	private function loadQuestions(int $formId): array {
+		$questions = [];
+		try {
+			foreach ($this->questionMapper->findByForm($formId) as $entity) {
+				$questions[] = $entity->read();
+			}
+		} catch (\Exception $e) {
+			$this->logger->debug('Failed to load questions for confirmation email placeholder substitution', [
+				'formId' => $formId,
+				'exception' => $e,
+			]);
+		}
+		return $questions;
+	}
+
+	/**
+	 * @return array<int, string[]>
+	 */
+	private function buildAnswerMap(Submission $submission): array {
+		$map = [];
+		foreach ($this->answerMapper->findBySubmission($submission->getId()) as $answer) {
+			$map[$answer->getQuestionId()][] = $answer->getText();
+		}
+		return $map;
+	}
+
+	/**
+	 * @param list<array<string, mixed>> $questions
+	 * @param array<int, string[]> $answerMap
+	 * @return array{string, string}
+	 */
+	private function buildEmailContent(Form $form, array $questions, array $answerMap): array {
+		$subject = $form->getConfirmationEmailSubject();
+		$body = $form->getConfirmationEmailBody();
+
+		if (empty($subject)) {
+			$subject = $this->l10n->t('Thank you for your submission');
+		}
+		if (empty($body)) {
+			$body = $this->l10n->t('Thank you for submitting the form "%s".', [$form->getTitle()]);
+		}
+
+		$replacements = [
+			'{formTitle}' => $form->getTitle(),
+			'{formDescription}' => $form->getDescription() ?? '',
+		];
+
+		foreach ($questions as $question) {
+			$fieldKey = !empty($question['name'] ?? '') ? $question['name'] : ($question['text'] ?? '');
+			$fieldKey = strtolower(preg_replace('/[^a-zA-Z0-9]/', '', $fieldKey));
+			if ($fieldKey === '' || empty($answerMap[$question['id']])) {
+				continue;
+			}
+			$placeholder = '{' . $fieldKey . '}';
+			if (isset($replacements[$placeholder])) {
+				$this->logger->warning('Confirmation email placeholder key collision, skipping duplicate', [
+					'formId' => $form->getId(),
+					'key' => $fieldKey,
+				]);
+				continue;
+			}
+			$replacements[$placeholder] = implode('; ', $answerMap[$question['id']]);
+		}
+
+		return [
+			str_replace(array_keys($replacements), array_values($replacements), $subject),
+			str_replace(array_keys($replacements), array_values($replacements), $body),
+		];
+	}
+
+	/**
+	 * @param list<array<string, mixed>> $questions
+	 * @return array<string, mixed>|null
+	 */
+	private function findRecipientQuestion(Form $form, array $questions): ?array {
+		$recipientQuestionId = $form->getConfirmationEmailQuestionId();
+		if ($recipientQuestionId === null) {
+			return null;
+		}
+
+		foreach ($questions as $questionData) {
+			if (($questionData['id'] ?? null) !== $recipientQuestionId) {
+				continue;
+			}
+
+			if (Question::checkEmailType(
+				$questionData['type'] ?? '',
+				(array)($questionData['extraSettings'] ?? [])
+			)) {
+				return $questionData;
+			}
+
+			return null;
+		}
+
+		return null;
+	}
+
+	private function checkRateLimit(string $email, int $formId, int $submissionId): bool {
+		$cacheKey = 'email_rl_' . hash('sha256', $formId . ':' . strtolower($email));
+
+		if (!$this->rateLimitCache instanceof IMemcache) {
+			// Atomic increment requires IMemcache; without it we cannot safely count.
+			$this->logger->debug('Distributed cache unavailable, skipping confirmation email rate limit', [
+				'formId' => $formId,
+			]);
+			return true;
+		}
+
+		$rateLimit = $this->configService->getConfirmationEmailRateLimit();
+
+		if ($this->rateLimitCache->add($cacheKey, 1, self::RATE_LIMIT_TTL)) {
+			$count = 1;
+		} else {
+			$count = $this->rateLimitCache->inc($cacheKey);
+			if (!is_int($count)) {
+				$this->logger->warning('Failed to increment confirmation email rate limit counter', [
+					'formId' => $formId,
+					'submissionId' => $submissionId,
+				]);
+				return false;
+			}
+		}
+
+		if ($count > $rateLimit) {
+			$this->logger->warning('Per-recipient confirmation email rate limit reached', [
+				'formId' => $formId,
+				'submissionId' => $submissionId,
+			]);
+			return false;
+		}
+
+		return true;
+	}
+}
diff --git a/lib/Service/FormsService.php b/lib/Service/FormsService.php
index f5b421c3a..d0e93f5b8 100644
--- a/lib/Service/FormsService.php
+++ b/lib/Service/FormsService.php
@@ -67,6 +67,7 @@ public function __construct(
 		private IL10N $l10n,
 		private LoggerInterface $logger,
 		private IEventDispatcher $eventDispatcher,
+		private ConfirmationEmailService $confirmationEmailService,
 	) {
 		$this->currentUser = $userSession->getUser();
 	}
@@ -739,6 +740,8 @@ public function notifyNewSubmission(Form $form, Submission $submission): void {
 		}
 
 		$this->eventDispatcher->dispatchTyped(new FormSubmittedEvent($form, $submission));
+
+		$this->confirmationEmailService->send($form, $submission);
 	}
 
 	/**
@@ -1015,4 +1018,5 @@ public function getTemporaryUploadedFilePath(Form $form, Question $question): st
 	private static function normalizeFileName(string $fileName): string {
 		return trim(str_replace(Constants::FILENAME_INVALID_CHARS, '-', $fileName));
 	}
+
 }
diff --git a/openapi.json b/openapi.json
index 9d80a1151..a423c4546 100644
--- a/openapi.json
+++ b/openapi.json
@@ -119,7 +119,11 @@
                     "lockedUntil",
                     "maxSubmissions",
                     "shares",
-                    "submissionMessage"
+                    "submissionMessage",
+                    "confirmationEmailEnabled",
+                    "confirmationEmailSubject",
+                    "confirmationEmailBody",
+                    "confirmationEmailQuestionId"
                 ],
                 "properties": {
                     "id": {
@@ -232,6 +236,22 @@
                     "submissionMessage": {
                         "type": "string",
                         "nullable": true
+                    },
+                    "confirmationEmailEnabled": {
+                        "type": "boolean"
+                    },
+                    "confirmationEmailSubject": {
+                        "type": "string",
+                        "nullable": true
+                    },
+                    "confirmationEmailBody": {
+                        "type": "string",
+                        "nullable": true
+                    },
+                    "confirmationEmailQuestionId": {
+                        "type": "integer",
+                        "format": "int64",
+                        "nullable": true
                     }
                 }
             },
diff --git a/src/FormsSettings.vue b/src/FormsSettings.vue
index 60c607c8e..46735d411 100644
--- a/src/FormsSettings.vue
+++ b/src/FormsSettings.vue
@@ -24,6 +24,37 @@
 				label="displayName"
 				@input="onCreationAllowedGroupsChange" />
 		</NcSettingsSection>
+		<NcSettingsSection
+			:name="t('forms', 'Confirmation emails')"
+			:description="
+				t(
+					'forms',
+					'Allow form owners to send a confirmation email to respondents after submission.',
+				)
+			">
+			<NcCheckboxRadioSwitch
+				ref="switchAllowConfirmationEmail"
+				v-model="appConfig.allowConfirmationEmail"
+				type="switch"
+				@update:modelValue="onAllowConfirmationEmailChange">
+				{{ t('forms', 'Allow confirmation emails to form respondents') }}
+			</NcCheckboxRadioSwitch>
+			<NcInputField
+				v-if="appConfig.allowConfirmationEmail"
+				v-model="confirmationEmailRateLimitInput"
+				:label="t('forms', 'Rate limit (emails per recipient per 24 hours)')"
+				:helperText="
+					t(
+						'forms',
+						'Maximum number of confirmation emails sent to the same address per 24 hours.',
+					)
+				"
+				type="number"
+				:min="1"
+				:max="100"
+				class="forms-settings__rate-limit"
+				@change="onConfirmationEmailRateLimitChange" />
+		</NcSettingsSection>
 		<NcSettingsSection :name="t('forms', 'Form sharing')">
 			<NcCheckboxRadioSwitch
 				ref="switchAllowPublicLink"
@@ -61,6 +92,7 @@ import { showError } from '@nextcloud/dialogs'
 import { loadState } from '@nextcloud/initial-state'
 import { generateUrl } from '@nextcloud/router'
 import NcCheckboxRadioSwitch from '@nextcloud/vue/components/NcCheckboxRadioSwitch'
+import NcInputField from '@nextcloud/vue/components/NcInputField'
 import NcSelect from '@nextcloud/vue/components/NcSelect'
 import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
 import logger from './utils/Logger.js'
@@ -70,6 +102,7 @@ export default {
 
 	components: {
 		NcCheckboxRadioSwitch,
+		NcInputField,
 		NcSelect,
 		NcSettingsSection,
 	},
@@ -78,6 +111,9 @@ export default {
 		return {
 			appConfig: loadState(appName, 'appConfig'),
 			availableGroups: loadState(appName, 'availableGroups'),
+			confirmationEmailRateLimitInput: String(
+				loadState(appName, 'appConfig').confirmationEmailRateLimit ?? 3,
+			),
 		}
 	},
 
@@ -129,6 +165,25 @@ export default {
 			el.loading = false
 		},
 
+		async onAllowConfirmationEmailChange(newVal) {
+			const el = this.$refs.switchAllowConfirmationEmail
+			el.loading = true
+			await this.saveAppConfig('allowConfirmationEmail', newVal)
+			el.loading = false
+		},
+
+		async onConfirmationEmailRateLimitChange() {
+			const value = Math.max(
+				1,
+				Math.min(
+					100,
+					parseInt(this.confirmationEmailRateLimitInput, 10) || 3,
+				),
+			)
+			this.confirmationEmailRateLimitInput = String(value)
+			await this.saveAppConfig('confirmationEmailRateLimit', value)
+		},
+
 		/**
 		 * Save a key-value pair to the appConfig.
 		 *
@@ -173,5 +228,10 @@ export default {
 	&__creation__multiselect {
 		width: 100%;
 	}
+
+	&__rate-limit {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+		max-width: 300px;
+	}
 }
 </style>
diff --git a/src/components/SidebarTabs/SettingsSidebarTab.vue b/src/components/SidebarTabs/SettingsSidebarTab.vue
index b973b6e54..723a37ee2 100644
--- a/src/components/SidebarTabs/SettingsSidebarTab.vue
+++ b/src/components/SidebarTabs/SettingsSidebarTab.vue
@@ -194,6 +194,70 @@
 			</div>
 		</div>
 
+		<template v-if="appConfig.allowConfirmationEmail">
+			<NcCheckboxRadioSwitch
+				:modelValue="form.confirmationEmailEnabled"
+				:disabled="formArchived || locked"
+				type="switch"
+				@update:modelValue="onConfirmationEmailEnabledChange">
+				{{ t('forms', 'Send confirmation email to respondents') }}
+			</NcCheckboxRadioSwitch>
+			<div
+				v-show="form.confirmationEmailEnabled && !formArchived"
+				class="settings-div--indent confirmation-email">
+				<NcNoteCard
+					v-if="confirmationEmailErrorText"
+					:type="confirmationEmailNoteCardType"
+					:text="confirmationEmailErrorText" />
+				<div
+					v-if="emailQuestionCount > 0"
+					class="confirmation-email__recipient">
+					<label
+						for="confirmation-email-recipient"
+						class="confirmation-email__label">
+						{{ t('forms', 'Recipient field') }}
+					</label>
+					<NcSelect
+						inputId="confirmation-email-recipient"
+						:modelValue="selectedConfirmationEmailQuestionOption"
+						:disabled="locked || emailQuestionCount === 1"
+						:options="confirmationEmailQuestionOptions"
+						:placeholder="t('forms', 'Select an email field')"
+						class="confirmation-email__select"
+						label="label"
+						:searchable="false"
+						:clearable="false"
+						trackBy="id"
+						@update:modelValue="
+							onConfirmationEmailQuestionIdSelectionChange
+						" />
+				</div>
+				<p class="confirmation-email__placeholder-hint">
+					{{ t('forms', 'Available placeholders:') }}
+					<code>{formTitle}</code>, <code>{formDescription}</code>,
+					{{ t('forms', 'and field labels.') }}
+				</p>
+				<NcInputField
+					v-model="confirmationEmailSubject"
+					:disabled="locked || isConfirmationEmailConfigurationBlocked"
+					:maxlength="255"
+					:placeholder="
+						t('forms', 'Thank you for your {formTitle} submission')
+					"
+					:label="t('forms', 'Email subject')"
+					class="confirmation-email__input"
+					@blur="onConfirmationEmailSubjectChange" />
+				<NcTextArea
+					v-model="confirmationEmailBody"
+					:disabled="locked || isConfirmationEmailConfigurationBlocked"
+					:placeholder="emailBodyPlaceholder"
+					:label="t('forms', 'Email body')"
+					:maxlength="8192"
+					class="confirmation-email__textarea"
+					@blur="onConfirmationEmailBodyChange" />
+			</div>
+		</template>
+
 		<TransferOwnership
 			:locked="locked"
 			:isOwner="isCurrentUserOwner"
@@ -212,6 +276,8 @@ import NcDateTimePicker from '@nextcloud/vue/components/NcDateTimePicker'
 import NcIconSvgWrapper from '@nextcloud/vue/components/NcIconSvgWrapper'
 import NcInputField from '@nextcloud/vue/components/NcInputField'
 import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
+import NcSelect from '@nextcloud/vue/components/NcSelect'
+import NcTextArea from '@nextcloud/vue/components/NcTextArea'
 import TransferOwnership from './TransferOwnership.vue'
 import svgLockOpen from '../../../img/lock_open.svg?raw'
 import ShareTypes from '../../mixins/ShareTypes.js'
@@ -225,6 +291,8 @@ export default {
 		NcDateTimePicker,
 		NcIconSvgWrapper,
 		NcNoteCard,
+		NcSelect,
+		NcTextArea,
 		TransferOwnership,
 	},
 
@@ -262,10 +330,13 @@ export default {
 				parse: this.parseTimestampToDate,
 			},
 
+			appConfig: loadState('forms', 'appConfig'),
 			maxStringLengths: loadState('forms', 'maxStringLengths'),
 			/** If custom submission message is shown as input or rendered markdown */
 			editMessage: false,
 			svgLockOpen,
+			confirmationEmailSubject: this.form?.confirmationEmailSubject || '',
+			confirmationEmailBody: this.form?.confirmationEmailBody || '',
 		}
 	},
 
@@ -361,9 +432,159 @@ export default {
 		submissionMessageHTML() {
 			return this.$markdownit.render(this.form.submissionMessage || '')
 		},
+
+		emailBodyPlaceholder() {
+			return t(
+				'forms',
+				'Hello,\n\nThank you for submitting the form "{formTitle}".\n\nBest regards',
+			)
+		},
+
+		emailQuestionCount() {
+			return this.confirmationEmailQuestions.length
+		},
+
+		confirmationEmailQuestions() {
+			const questions = this.form?.questions || []
+			return questions.filter(
+				(question) =>
+					question.type === 'short'
+					&& question.extraSettings?.validationType === 'email',
+			)
+		},
+
+		selectedConfirmationEmailQuestion() {
+			const selectedQuestion = this.confirmationEmailQuestions.find(
+				(question) => question.id === this.form.confirmationEmailQuestionId,
+			)
+			if (selectedQuestion) {
+				return selectedQuestion
+			}
+
+			if (
+				this.form.confirmationEmailQuestionId === null
+				&& this.emailQuestionCount === 1
+			) {
+				return this.confirmationEmailQuestions[0]
+			}
+
+			return null
+		},
+
+		selectedConfirmationEmailQuestionId() {
+			return (
+				this.form.confirmationEmailQuestionId
+				?? this.selectedConfirmationEmailQuestion?.id
+				?? ''
+			)
+		},
+
+		confirmationEmailQuestionOptions() {
+			return this.confirmationEmailQuestions.map((question) => ({
+				id: question.id,
+				label: this.confirmationEmailQuestionLabel(question),
+			}))
+		},
+
+		selectedConfirmationEmailQuestionOption() {
+			return (
+				this.confirmationEmailQuestionOptions.find(
+					(question) =>
+						question.id === this.selectedConfirmationEmailQuestionId,
+				) || null
+			)
+		},
+
+		confirmationEmailErrorText() {
+			if (this.emailQuestionCount === 0) {
+				return t(
+					'forms',
+					'Add at least one email field before confirmation emails can be used.',
+				)
+			}
+
+			if (this.requiresConfirmationEmailQuestionIdSelection) {
+				return t(
+					'forms',
+					'Select which email field should receive confirmation emails before finishing this setup.',
+				)
+			}
+
+			return ''
+		},
+
+		confirmationEmailNoteCardType() {
+			if (this.requiresConfirmationEmailQuestionIdSelection) {
+				return 'warning'
+			}
+			return 'info'
+		},
+
+		requiresConfirmationEmailQuestionIdSelection() {
+			return (
+				this.emailQuestionCount > 1
+				&& !this.selectedConfirmationEmailQuestion
+			)
+		},
+
+		isConfirmationEmailConfigurationBlocked() {
+			return (
+				this.form.confirmationEmailEnabled
+				&& (this.emailQuestionCount === 0
+					|| this.requiresConfirmationEmailQuestionIdSelection)
+			)
+		},
+	},
+
+	watch: {
+		'form.confirmationEmailSubject': function (val) {
+			this.confirmationEmailSubject = val || ''
+		},
+
+		'form.confirmationEmailBody': function (val) {
+			this.confirmationEmailBody = val || ''
+		},
+
+		confirmationEmailQuestions: {
+			handler() {
+				const selectedRecipientId = this.form.confirmationEmailQuestionId
+				const hasValidSelectedRecipient =
+					selectedRecipientId !== null
+					&& this.confirmationEmailQuestions.some(
+						(question) => question.id === selectedRecipientId,
+					)
+
+				if (selectedRecipientId !== null && !hasValidSelectedRecipient) {
+					if (this.emailQuestionCount === 1) {
+						this.saveConfirmationEmailQuestionId(
+							this.confirmationEmailQuestions[0].id,
+						)
+					} else {
+						this.saveConfirmationEmailQuestionId(null)
+					}
+					return
+				}
+
+				if (
+					this.form.confirmationEmailEnabled
+					&& this.emailQuestionCount === 1
+					&& this.form.confirmationEmailQuestionId === null
+				) {
+					this.saveConfirmationEmailQuestionId(
+						this.confirmationEmailQuestions[0].id,
+					)
+				}
+			},
+
+			deep: true,
+		},
 	},
 
 	methods: {
+		confirmationEmailQuestionLabel(question) {
+			return question.text || t('forms', 'Untitled question')
+		},
+
 		/**
 		 * Save Form-Properties
 		 *
@@ -456,6 +677,57 @@ export default {
 			}
 		},
 
+		onConfirmationEmailEnabledChange(checked) {
+			if (
+				checked
+				&& this.form.confirmationEmailQuestionId === null
+				&& this.emailQuestionCount === 1
+			) {
+				this.saveConfirmationEmailQuestionId(
+					this.confirmationEmailQuestions[0].id,
+				)
+			}
+
+			this.$emit('update:formProp', 'confirmationEmailEnabled', checked)
+		},
+
+		onConfirmationEmailSubjectChange() {
+			this.$emit(
+				'update:formProp',
+				'confirmationEmailSubject',
+				this.confirmationEmailSubject,
+			)
+		},
+
+		onConfirmationEmailBodyChange() {
+			this.$emit(
+				'update:formProp',
+				'confirmationEmailBody',
+				this.confirmationEmailBody,
+			)
+		},
+
+		onConfirmationEmailQuestionIdSelectionChange(option) {
+			const questionId = option?.id ?? null
+			if (questionId === null) {
+				return
+			}
+
+			this.saveConfirmationEmailQuestionId(questionId)
+		},
+
+		saveConfirmationEmailQuestionId(selectedQuestionId) {
+			if (this.form.confirmationEmailQuestionId === selectedQuestionId) {
+				return
+			}
+
+			this.$emit(
+				'update:formProp',
+				'confirmationEmailQuestionId',
+				selectedQuestionId,
+			)
+		},
+
 		/**
 		 * Datepicker timestamp to string
 		 *
@@ -550,4 +822,42 @@ export default {
 		}
 	}
 }
+
+.confirmation-email {
+	&__recipient {
+		margin-bottom: calc(var(--default-grid-baseline) * 3);
+	}
+
+	&__label {
+		display: block;
+		overflow: hidden;
+		text-overflow: ellipsis;
+		white-space: nowrap;
+		margin-bottom: var(--default-grid-baseline);
+		font-weight: 600;
+		color: var(--color-text-maxcontrast);
+	}
+
+	&__placeholder-hint {
+		color: var(--color-text-maxcontrast);
+		font-size: var(--font-size-small);
+		margin-top: calc(var(--default-grid-baseline) * 2);
+	}
+
+	&__select {
+		width: 100%;
+
+		// NcSelect sets min-width: 260px with two-class specificity; double
+		// our class to win the cascade without !important.
+		&#{&} {
+			min-width: 0;
+		}
+	}
+
+	&__input,
+	&__textarea {
+		width: 100%;
+		margin-top: calc(var(--default-grid-baseline) * 3);
+	}
+}
 </style>
diff --git a/tests/Integration/Api/ApiV3Test.php b/tests/Integration/Api/ApiV3Test.php
index 0605ffe91..e7378d287 100644
--- a/tests/Integration/Api/ApiV3Test.php
+++ b/tests/Integration/Api/ApiV3Test.php
@@ -397,6 +397,10 @@ public static function dataGetNewForm() {
 					'fileFormat' => null,
 					'maxSubmissions' => null,
 					'isMaxSubmissionsReached' => false,
+					'confirmationEmailEnabled' => false,
+					'confirmationEmailSubject' => null,
+					'confirmationEmailBody' => null,
+					'confirmationEmailQuestionId' => null,
 				]
 			]
 		];
@@ -530,6 +534,10 @@ public static function dataGetFullForm() {
 					'fileFormat' => null,
 					'maxSubmissions' => null,
 					'isMaxSubmissionsReached' => false,
+					'confirmationEmailEnabled' => false,
+					'confirmationEmailSubject' => null,
+					'confirmationEmailBody' => null,
+					'confirmationEmailQuestionId' => null,
 				]
 			]
 		];
diff --git a/tests/Integration/Api/RespectAdminSettingsTest.php b/tests/Integration/Api/RespectAdminSettingsTest.php
index 09d8ff7d1..29e088985 100644
--- a/tests/Integration/Api/RespectAdminSettingsTest.php
+++ b/tests/Integration/Api/RespectAdminSettingsTest.php
@@ -145,6 +145,10 @@ private static function sharedTestForms(): array {
 				'submissionCount' => 0,
 				'maxSubmissions' => null,
 				'isMaxSubmissionsReached' => false,
+				'confirmationEmailEnabled' => false,
+				'confirmationEmailSubject' => null,
+				'confirmationEmailBody' => null,
+				'confirmationEmailQuestionId' => null,
 			],
 		];
 	}
diff --git a/tests/Unit/Controller/ApiControllerTest.php b/tests/Unit/Controller/ApiControllerTest.php
index 28c77c60b..89ef8478d 100644
--- a/tests/Unit/Controller/ApiControllerTest.php
+++ b/tests/Unit/Controller/ApiControllerTest.php
@@ -45,6 +45,7 @@ function is_uploaded_file(string|bool|null $filename) {
 use OCA\Forms\Db\UploadedFileMapper;
 use OCA\Forms\Exception\NoSuchFormException;
 use OCA\Forms\Service\ConfigService;
+use OCA\Forms\Service\ConfirmationEmailService;
 use OCA\Forms\Service\FormsService;
 use OCA\Forms\Service\SubmissionService;
 use OCP\AppFramework\Db\DoesNotExistException;
@@ -85,6 +86,8 @@ class ApiControllerTest extends TestCase {
 	private $shareMapper;
 	/** @var SubmissionMapper|MockObject */
 	private $submissionMapper;
+	/** @var ConfirmationEmailService|MockObject */
+	private $confirmationEmailService;
 	/** @var ConfigService|MockObject */
 	private $configService;
 	/** @var FormsService|MockObject */
@@ -115,6 +118,7 @@ public function setUp(): void {
 		$this->questionMapper = $this->createMock(QuestionMapper::class);
 		$this->shareMapper = $this->createMock(ShareMapper::class);
 		$this->submissionMapper = $this->createMock(SubmissionMapper::class);
+		$this->confirmationEmailService = $this->createMock(ConfirmationEmailService::class);
 		$this->configService = $this->createMock(ConfigService::class);
 		$this->formsService = $this->createMock(FormsService::class);
 		$this->submissionService = $this->createMock(SubmissionService::class);
@@ -142,6 +146,7 @@ public function setUp(): void {
 			$this->questionMapper,
 			$this->shareMapper,
 			$this->submissionMapper,
+			$this->confirmationEmailService,
 			$this->configService,
 			$this->formsService,
 			$this->submissionService,
@@ -516,6 +521,10 @@ public static function dataTestCreateNewForm() {
 				'lockedBy' => null,
 				'lockedUntil' => null,
 				'maxSubmissions' => null,
+				'confirmationEmailEnabled' => false,
+				'confirmationEmailSubject' => null,
+				'confirmationEmailBody' => null,
+				'confirmationEmailQuestionId' => null,
 			]]
 		];
 	}
@@ -534,7 +543,11 @@ public function testCreateNewForm($expectedForm) {
 		$expected['id'] = null;
 		// TODO fix test, currently unset because behaviour has changed
 		$expected['state'] = null;
-		$expected['lastUpdated'] = null;
+		$expected['lastUpdated'] = 0;
+		$expected['confirmationEmailEnabled'] = false;
+		$expected['confirmationEmailSubject'] = null;
+		$expected['confirmationEmailBody'] = null;
+		$expected['confirmationEmailQuestionId'] = null;
 		$this->formMapper->expects($this->once())
 			->method('insert')
 			->with(self::callback(self::createFormValidator($expected)))
@@ -1149,6 +1162,190 @@ public function testDeleteAllSubmissionsWithResultsDeletePermission(): void {
 		$this->assertEquals(new DataResponse(1), $this->apiController->deleteAllSubmissions(1));
 	}
 
+	public function testUpdateFormAllowsValidConfirmationEmailQuestionId(): void {
+		$form = new Form();
+		$form->setId(1);
+		$form->setOwnerId('currentUser');
+
+		$this->formsService
+			->method('getFormIfAllowed')
+			->with(1, Constants::PERMISSION_EDIT)
+			->willReturn($form);
+
+		$this->confirmationEmailService->expects($this->once())
+			->method('validateRecipientQuestionId')
+			->with($form, 7);
+
+		$this->formMapper->expects($this->once())
+			->method('update')
+			->with($form);
+
+		$this->assertEquals(new DataResponse(1), $this->apiController->updateForm(1, ['confirmationEmailQuestionId' => 7]));
+		$this->assertSame(7, $form->getConfirmationEmailQuestionId());
+	}
+
+	public static function dataUpdateFormRejectsInvalidConfirmationEmailQuestionId(): array {
+		return [
+			'invalid-question-id' => ['Invalid question ID'],
+			'question-from-another-form' => ['Question belongs to a different form'],
+			'deleted-question' => ['Question has been deleted'],
+		];
+	}
+
+	/**
+	 * @dataProvider dataUpdateFormRejectsInvalidConfirmationEmailQuestionId
+	 */
+	public function testUpdateFormRejectsInvalidConfirmationEmailQuestionId(string $reason): void {
+		$form = new Form();
+		$form->setId(1);
+		$form->setOwnerId('currentUser');
+
+		$this->formsService
+			->method('getFormIfAllowed')
+			->with(1, Constants::PERMISSION_EDIT)
+			->willReturn($form);
+
+		$this->confirmationEmailService->expects($this->once())
+			->method('validateRecipientQuestionId')
+			->with($form, 7)
+			->willThrowException(new \InvalidArgumentException($reason));
+
+		$this->formMapper->expects($this->never())->method('update');
+
+		$this->expectException(OCSBadRequestException::class);
+		$this->apiController->updateForm(1, ['confirmationEmailQuestionId' => 7]);
+	}
+
+	public function testUpdateQuestionClearsConfirmationEmailQuestionIdWhenQuestionStopsBeingEmail(): void {
+		$form = new Form();
+		$form->setId(1);
+		$form->setOwnerId('currentUser');
+		$form->setConfirmationEmailQuestionId(7);
+
+		$question = new Question();
+		$question->setId(7);
+		$question->setFormId(1);
+		$question->setType(Constants::ANSWER_TYPE_SHORT);
+		$question->setExtraSettings(['validationType' => 'email']);
+
+		$this->formsService
+			->method('getFormIfAllowed')
+			->with(1, Constants::PERMISSION_EDIT)
+			->willReturn($form);
+		$this->formsService
+			->method('isFormArchived')
+			->with($form)
+			->willReturn(false);
+		$this->formsService
+			->method('areExtraSettingsValid')
+			->with(['validationType' => 'text'], Constants::ANSWER_TYPE_SHORT)
+			->willReturn(true);
+
+		$this->questionMapper->expects($this->once())
+			->method('findById')
+			->with(7)
+			->willReturn($question);
+		$this->questionMapper->expects($this->once())
+			->method('update')
+			->with($this->callback(function (Question $updatedQuestion): bool {
+				return $updatedQuestion->getId() === 7;
+			}));
+
+		$this->formMapper->expects($this->once())
+			->method('update')
+			->with($form);
+
+		$this->assertEquals(new DataResponse(7), $this->apiController->updateQuestion(1, 7, [
+			'extraSettings' => ['validationType' => 'text'],
+		]));
+		$this->assertNull($form->getConfirmationEmailQuestionId());
+	}
+
+	public function testDeleteQuestionClearsConfirmationEmailQuestionIdWhenDeletingSelectedQuestion(): void {
+		$form = new Form();
+		$form->setId(1);
+		$form->setOwnerId('currentUser');
+		$form->setConfirmationEmailQuestionId(7);
+
+		$question = new Question();
+		$question->setId(7);
+		$question->setFormId(1);
+		$question->setOrder(1);
+
+		$this->formsService
+			->method('getFormIfAllowed')
+			->with(1, Constants::PERMISSION_EDIT)
+			->willReturn($form);
+		$this->formsService
+			->method('isFormArchived')
+			->with($form)
+			->willReturn(false);
+
+		$this->questionMapper->expects($this->once())
+			->method('findById')
+			->with(7)
+			->willReturn($question);
+		$this->questionMapper->expects($this->once())
+			->method('findByForm')
+			->with(1)
+			->willReturn([]);
+		$this->questionMapper->expects($this->once())
+			->method('update')
+			->with($this->callback(function (Question $updatedQuestion): bool {
+				return $updatedQuestion->getId() === 7 && $updatedQuestion->getOrder() === 0;
+			}));
+
+		$this->formMapper->expects($this->once())
+			->method('update')
+			->with($form);
+
+		$this->assertEquals(new DataResponse(7), $this->apiController->deleteQuestion(1, 7));
+		$this->assertNull($form->getConfirmationEmailQuestionId());
+	}
+
+	public function testCloneFormWithConfirmationEmailQuestionId(): void {
+		$this->configService->method('canCreateForms')->willReturn(true);
+
+		$oldForm = Form::fromParams([
+			'id' => 7,
+			'title' => 'Old Form',
+			'ownerId' => 'currentUser',
+			'confirmationEmailQuestionId' => 10,
+		]);
+		$this->formsService->method('getFormIfAllowed')->with(7)->willReturn($oldForm);
+		$this->formsService->method('generateFormHash')->willReturn('new hash');
+
+		$question = new Question();
+		$question->setId(10);
+		$question->setFormId(7);
+		$this->questionMapper->method('findByForm')->with(7)->willReturn([$question]);
+
+		$clonedForm = null;
+		$this->formMapper->expects($this->once())
+			->method('insert')
+			->with($this->callback(function (Form $form) use (&$clonedForm) {
+				$form->setId(14);
+				$clonedForm = $form;
+				return true;
+			}));
+
+		$this->questionMapper->expects($this->once())
+			->method('insert')
+			->with($this->callback(function (Question $newQuestion) {
+				$newQuestion->setId(11);
+				return true;
+			}));
+
+		$this->formMapper->expects($this->once())
+			->method('update')
+			->with($this->callback(function (Form $form) {
+				return $form->getId() === 14 && $form->getConfirmationEmailQuestionId() === 11;
+			}));
+
+		$this->apiController->newForm(7);
+		$this->assertEquals(11, $clonedForm->getConfirmationEmailQuestionId());
+	}
+
 	public function testTransferOwnerNotOwner() {
 		$form = new Form();
 		$form->setId(1);
diff --git a/tests/Unit/Db/QuestionTest.php b/tests/Unit/Db/QuestionTest.php
new file mode 100644
index 000000000..ebc58f72d
--- /dev/null
+++ b/tests/Unit/Db/QuestionTest.php
@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Forms\Tests\Unit\Db;
+
+use OCA\Forms\Constants;
+use OCA\Forms\Db\Question;
+use Test\TestCase;
+
+class QuestionTest extends TestCase {
+	/**
+	 * @dataProvider isEmailTypeData
+	 */
+	public function testIsEmailTypeStatic(string $type, array $extraSettings, bool $expected): void {
+		$this->assertSame($expected, Question::checkEmailType($type, $extraSettings));
+	}
+
+	public static function isEmailTypeData(): array {
+		return [
+			'valid-email' => [
+				Constants::ANSWER_TYPE_SHORT,
+				['validationType' => 'email'],
+				true
+			],
+			'invalid-type-long' => [
+				Constants::ANSWER_TYPE_LONG,
+				['validationType' => 'email'],
+				false
+			],
+			'invalid-validation-type-text' => [
+				Constants::ANSWER_TYPE_SHORT,
+				['validationType' => 'text'],
+				false
+			],
+			'invalid-validation-type-none' => [
+				Constants::ANSWER_TYPE_SHORT,
+				[],
+				false
+			],
+			'invalid-type-multiple' => [
+				Constants::ANSWER_TYPE_MULTIPLE,
+				['validationType' => 'email'],
+				false
+			],
+		];
+	}
+
+	public function testIsEmailTypeEntity(): void {
+		$question = new Question();
+		$question->setType(Constants::ANSWER_TYPE_SHORT);
+		$question->setExtraSettings(['validationType' => 'email']);
+
+		$this->assertTrue($question->isEmailType());
+
+		$question->setExtraSettings(['validationType' => 'text']);
+		$this->assertFalse($question->isEmailType());
+	}
+}
diff --git a/tests/Unit/FormsMigratorTest.php b/tests/Unit/FormsMigratorTest.php
index 97f584a6c..6113ce8a2 100644
--- a/tests/Unit/FormsMigratorTest.php
+++ b/tests/Unit/FormsMigratorTest.php
@@ -111,8 +111,12 @@ public static function dataExport() {
     "allowEditSubmissions": false,
     "showExpiration": false,
     "lastUpdated": 123456789,
-    "submissionMessage": "Back to website",
-    "questions": [
+	    "submissionMessage": "Back to website",
+	    "confirmationEmailEnabled": false,
+	    "confirmationEmailSubject": "Thanks",
+	    "confirmationEmailBody": "Body",
+	    "confirmationEmailQuestionId": null,
+	    "questions": [
       {
         "id": 14,
         "order": 2,
@@ -186,6 +190,10 @@ public function testExport(string $expectedJson) {
 		$form->setShowExpiration(false);
 		$form->setLastUpdated(123456789);
 		$form->setSubmissionMessage('Back to website');
+		$form->setConfirmationEmailEnabled(false);
+		$form->setConfirmationEmailSubject('Thanks');
+		$form->setConfirmationEmailBody('Body');
+		$form->setConfirmationEmailQuestionId(null);
 
 		$this->formsService->expects($this->once())
 			->method('getQuestions')
@@ -255,7 +263,7 @@ public function testExport(string $expectedJson) {
 	public static function dataImport() {
 		return [
 			'exactlyOneOfEach' => [
-				'inputJson' => '[{"title":"Link","description":"","created":1646251830,"access":{"permitAllUsers":false,"showToAllUsers":false},"expires":0,"state":0,"lockedBy":null,"lockedUntil":null,"maxSubmissions":null,"isAnonymous":false,"submitMultiple":false,"allowEditSubmissions":false,"showExpiration":false,"lastUpdated":123456789,"questions":[{"id":14,"order":2,"type":"multiple","isRequired":false,"text":"checkbox","description":"huhu","extraSettings":{},"options":[{"text":"ans1"}]}],"submissions":[{"userId":"anyUser@localhost","timestamp":1651354059,"answers":[{"questionId":14,"text":"ans1"}]}]}]'
+				'inputJson' => '[{"title":"Link","description":"","created":1646251830,"access":{"permitAllUsers":false,"showToAllUsers":false},"expires":0,"state":0,"lockedBy":null,"lockedUntil":null,"maxSubmissions":null,"isAnonymous":false,"submitMultiple":false,"allowEditSubmissions":false,"showExpiration":false,"lastUpdated":123456789,"confirmationEmailEnabled":true,"confirmationEmailSubject":"Thanks","confirmationEmailBody":"Body","confirmationEmailQuestionId":null,"questions":[{"id":14,"order":2,"type":"multiple","isRequired":false,"text":"checkbox","description":"huhu","extraSettings":{},"options":[{"text":"ans1"}]}],"submissions":[{"userId":"anyUser@localhost","timestamp":1651354059,"answers":[{"questionId":14,"text":"ans1"}]}]}]'
 			]
 		];
 	}
@@ -285,7 +293,14 @@ public function testImport(string $inputJson) {
 			->method('generateFormHash')
 			->willReturn('abcdefg');
 
-		$this->formMapper->expects($this->once())->method('insert');
+		$this->formMapper->expects($this->once())
+			->method('insert')
+			->willReturnCallback(function (Form $form) {
+				$this->assertTrue($form->getConfirmationEmailEnabled());
+				$this->assertSame('Thanks', $form->getConfirmationEmailSubject());
+				$this->assertSame('Body', $form->getConfirmationEmailBody());
+				return $form;
+			});
 		$this->questionMapper->expects($this->once())->method('insert');
 		$this->optionMapper->expects($this->once())->method('insert');
 		$this->submissionMapper->expects($this->once())->method('insert');
diff --git a/tests/Unit/Service/ConfigServiceTest.php b/tests/Unit/Service/ConfigServiceTest.php
index d0ff7a420..30fdfd169 100644
--- a/tests/Unit/Service/ConfigServiceTest.php
+++ b/tests/Unit/Service/ConfigServiceTest.php
@@ -9,6 +9,7 @@
 
 use OCA\Forms\Service\ConfigService;
 
+use OCP\AppFramework\Services\IAppConfig;
 use OCP\IConfig;
 use OCP\IGroup;
 use OCP\IGroupManager;
@@ -27,6 +28,9 @@ class ConfigServiceTest extends TestCase {
 	/** @var IConfig|MockObject */
 	private $config;
 
+	/** @var IAppConfig|MockObject */
+	private $appConfig;
+
 	/** @var IGroupManager|MockObject */
 	private $groupManager;
 
@@ -37,6 +41,7 @@ public function setUp(): void {
 		parent::setUp();
 
 		$this->config = $this->createMock(IConfig::class);
+		$this->appConfig = $this->createMock(IAppConfig::class);
 		$this->groupManager = $this->createMock(IGroupManager::class);
 		$userSession = $this->createMock(IUserSession::class);
 
@@ -51,6 +56,7 @@ public function setUp(): void {
 		$this->configService = new ConfigService(
 			'forms',
 			$this->config,
+			$this->appConfig,
 			$this->groupManager,
 			$userSession
 		);
@@ -65,6 +71,8 @@ public static function dataGetAppConfig() {
 					'allowShowToAll' => 'false',
 					'creationAllowedGroups' => '["group1", "group2", "nonExisting"]',
 					'restrictCreation' => 'true',
+					'allowConfirmationEmail' => 'false',
+					'confirmationEmailRateLimit' => '5',
 				],
 				'groupDisplayNames' => [
 					'group1' => 'Group No. 1',
@@ -85,7 +93,8 @@ public static function dataGetAppConfig() {
 						]
 					],
 					'restrictCreation' => true,
-
+					'allowConfirmationEmail' => false,
+					'confirmationEmailRateLimit' => 5,
 					'canCreateForms' => false
 				]
 			]
@@ -103,7 +112,7 @@ public function testGetAppConfig(array $strConfig, array $groupDisplayNames, arr
 		$this->config->expects($this->any())
 			->method('getAppValue')
 			->will($this->returnCallback(function ($appName, $configKey, $defaultVal) use ($strConfig) {
-				return $strConfig[$configKey];
+				return $strConfig[$configKey] ?? $defaultVal;
 			}));
 
 
@@ -127,6 +136,13 @@ public function testGetAppConfig(array $strConfig, array $groupDisplayNames, arr
 			->with($this->currentUser)
 			->willReturn([]);
 
+		$this->appConfig->expects($this->any())
+			->method('getAppValueBool')
+			->willReturn($expected['allowConfirmationEmail']);
+		$this->appConfig->expects($this->any())
+			->method('getAppValueInt')
+			->willReturn($expected['confirmationEmailRateLimit']);
+
 		$this->assertEquals($expected, $this->configService->getAppConfig());
 	}
 
@@ -139,6 +155,8 @@ public static function dataGetAppConfig_Default() {
 					'allowShowToAll' => true,
 					'creationAllowedGroups' => [],
 					'restrictCreation' => false,
+					'allowConfirmationEmail' => false,
+					'confirmationEmailRateLimit' => 3,
 					'canCreateForms' => true
 				]
 			]
@@ -157,6 +175,13 @@ public function testGetAppConfig_Default(array $expected) {
 				return $defaultVal;
 			}));
 
+		$this->appConfig->expects($this->any())
+			->method('getAppValueBool')
+			->willReturn($expected['allowConfirmationEmail']);
+		$this->appConfig->expects($this->any())
+			->method('getAppValueInt')
+			->willReturn($expected['confirmationEmailRateLimit']);
+
 		$this->assertEquals($expected, $this->configService->getAppConfig());
 	}
 
diff --git a/tests/Unit/Service/ConfirmationEmailServiceTest.php b/tests/Unit/Service/ConfirmationEmailServiceTest.php
new file mode 100644
index 000000000..afc819872
--- /dev/null
+++ b/tests/Unit/Service/ConfirmationEmailServiceTest.php
@@ -0,0 +1,465 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Forms\Tests\Unit\Service;
+
+use OCA\Forms\BackgroundJob\SendConfirmationMailJob;
+use OCA\Forms\Constants;
+use OCA\Forms\Db\Answer;
+use OCA\Forms\Db\AnswerMapper;
+use OCA\Forms\Db\Form;
+use OCA\Forms\Db\Question;
+use OCA\Forms\Db\QuestionMapper;
+use OCA\Forms\Db\Submission;
+use OCA\Forms\Service\ConfigService;
+use OCA\Forms\Service\ConfirmationEmailService;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\BackgroundJob\IJobList;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IL10N;
+use OCP\IMemcache;
+use OCP\Mail\IEmailValidator;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use Test\TestCase;
+
+class ConfirmationEmailServiceTest extends TestCase {
+	/** @var ConfirmationEmailService */
+	private $service;
+
+	/** @var ConfigService|MockObject */
+	private $configService;
+
+	/** @var AnswerMapper|MockObject */
+	private $answerMapper;
+
+	/** @var QuestionMapper|MockObject */
+	private $questionMapper;
+
+	/** @var IEmailValidator|MockObject */
+	private $emailValidator;
+
+	/** @var IJobList|MockObject */
+	private $jobList;
+
+	/** @var ICacheFactory|MockObject */
+	private $cacheFactory;
+
+	/** @var IMemcache|MockObject */
+	private $cache;
+
+	/** @var IL10N|MockObject */
+	private $l10n;
+
+	/** @var LoggerInterface|MockObject */
+	private $logger;
+
+	public function setUp(): void {
+		parent::setUp();
+
+		$this->configService = $this->createMock(ConfigService::class);
+		$this->answerMapper = $this->createMock(AnswerMapper::class);
+		$this->questionMapper = $this->createMock(QuestionMapper::class);
+		$this->emailValidator = $this->createMock(IEmailValidator::class);
+		$this->jobList = $this->createMock(IJobList::class);
+		$this->cacheFactory = $this->createMock(ICacheFactory::class);
+		$this->cache = $this->createMock(IMemcache::class);
+		$this->l10n = $this->createMock(IL10N::class);
+		$this->logger = $this->createMock(LoggerInterface::class);
+
+		$this->l10n->method('t')->willReturnCallback(
+			fn (string $text, array $params = []) => $params ? vsprintf($text, $params) : $text
+		);
+
+		$this->cacheFactory->method('createDistributed')
+			->with('forms_confirmation_email')
+			->willReturn($this->cache);
+
+		$this->service = new ConfirmationEmailService(
+			$this->configService,
+			$this->answerMapper,
+			$this->questionMapper,
+			$this->emailValidator,
+			$this->jobList,
+			$this->cacheFactory,
+			$this->l10n,
+			$this->logger,
+		);
+	}
+
+	private function createQuestionEntity(array $data): MockObject {
+		$entity = $this->createMock(Question::class);
+		$entity->method('read')->willReturn($data);
+		return $entity;
+	}
+
+	private function makeEmailAnswer(int $submissionId, int $questionId, string $email): Answer {
+		$answer = new Answer();
+		$answer->setSubmissionId($submissionId);
+		$answer->setQuestionId($questionId);
+		$answer->setText($email);
+		return $answer;
+	}
+
+	public function testSendDoesNothingIfConfirmationEmailDisabled(): void {
+		$form = Form::fromParams(['id' => 1, 'confirmationEmailEnabled' => false]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingIfAdminDisabled(): void {
+		$form = Form::fromParams(['id' => 1, 'confirmationEmailEnabled' => true]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(false);
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingIfNoRecipientQuestion(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => null,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->questionMapper->method('findByForm')->willReturn([]);
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingIfRecipientQuestionChangedType(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity(['id' => 5, 'type' => Constants::ANSWER_TYPE_LONG]),
+		]);
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingIfNoEmailAnswer(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+		$this->answerMapper->method('findBySubmission')->willReturn([]);
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingIfEmailAnswerIsInvalid(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+		$this->answerMapper->method('findBySubmission')->willReturn([
+			$this->makeEmailAnswer(10, 5, 'not-an-email'),
+		]);
+		$this->emailValidator->method('isValid')->with('not-an-email')->willReturn(false);
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendQueuesJobWithDefaultSubjectAndBody(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'title' => 'My Form',
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->configService->method('getConfirmationEmailRateLimit')->willReturn(3);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+		$this->answerMapper->method('findBySubmission')->willReturn([
+			$this->makeEmailAnswer(10, 5, 'user@example.com'),
+		]);
+		$this->emailValidator->method('isValid')->with('user@example.com')->willReturn(true);
+
+		$this->cache->method('add')->willReturn(true);
+
+		$this->jobList->expects($this->once())
+			->method('add')
+			->with(
+				SendConfirmationMailJob::class,
+				$this->callback(function (array $payload): bool {
+					$this->assertSame('user@example.com', $payload['recipient']);
+					$this->assertSame('Thank you for your submission', $payload['subject']);
+					$this->assertStringContainsString('My Form', $payload['body']);
+					$this->assertSame(1, $payload['formId']);
+					$this->assertSame(10, $payload['submissionId']);
+					return true;
+				})
+			);
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendQueuesJobWithCustomSubjectAndBodyAndPlaceholders(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'title' => 'Survey',
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+			'confirmationEmailSubject' => 'Hi {name}',
+			'confirmationEmailBody' => 'Your answer: {email}',
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->configService->method('getConfirmationEmailRateLimit')->willReturn(3);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 3,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'text' => 'Name',
+				'name' => 'name',
+			]),
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'text' => 'Email',
+				'name' => 'email',
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+
+		$nameAnswer = new Answer();
+		$nameAnswer->setSubmissionId(10);
+		$nameAnswer->setQuestionId(3);
+		$nameAnswer->setText('Alice');
+
+		$emailAnswer = $this->makeEmailAnswer(10, 5, 'alice@example.com');
+
+		$this->answerMapper->method('findBySubmission')->willReturn([$nameAnswer, $emailAnswer]);
+		$this->emailValidator->method('isValid')->willReturn(true);
+
+		$this->cache->method('add')->willReturn(true);
+
+		$this->jobList->expects($this->once())
+			->method('add')
+			->with(
+				SendConfirmationMailJob::class,
+				$this->callback(function (array $payload): bool {
+					$this->assertSame('Hi Alice', $payload['subject']);
+					$this->assertSame('Your answer: alice@example.com', $payload['body']);
+					return true;
+				})
+			);
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendDoesNothingWhenRateLimitExceeded(): void {
+		$form = Form::fromParams([
+			'id' => 1,
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->configService->method('getConfirmationEmailRateLimit')->willReturn(3);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+		$this->answerMapper->method('findBySubmission')->willReturn([
+			$this->makeEmailAnswer(10, 5, 'user@example.com'),
+		]);
+		$this->emailValidator->method('isValid')->willReturn(true);
+
+		$this->cache->method('add')->willReturn(false);
+		$this->cache->method('inc')->willReturn(4); // exceeds limit of 3
+
+		$this->jobList->expects($this->never())->method('add');
+
+		$this->service->send($form, $submission);
+	}
+
+	public function testSendSkipsRateLimitWhenCacheIsNotIMemcache(): void {
+		$plainCache = $this->createMock(ICache::class);
+		$this->cacheFactory = $this->createMock(ICacheFactory::class);
+		$this->cacheFactory->method('createDistributed')->willReturn($plainCache);
+
+		$service = new ConfirmationEmailService(
+			$this->configService,
+			$this->answerMapper,
+			$this->questionMapper,
+			$this->emailValidator,
+			$this->jobList,
+			$this->cacheFactory,
+			$this->l10n,
+			$this->logger,
+		);
+
+		$form = Form::fromParams([
+			'id' => 1,
+			'title' => 'Test',
+			'confirmationEmailEnabled' => true,
+			'confirmationEmailQuestionId' => 5,
+		]);
+		$submission = new Submission();
+		$submission->setId(10);
+
+		$this->configService->method('getAllowConfirmationEmail')->willReturn(true);
+		$this->questionMapper->method('findByForm')->willReturn([
+			$this->createQuestionEntity([
+				'id' => 5,
+				'type' => Constants::ANSWER_TYPE_SHORT,
+				'extraSettings' => ['validationType' => 'email'],
+			]),
+		]);
+		$this->answerMapper->method('findBySubmission')->willReturn([
+			$this->makeEmailAnswer(10, 5, 'user@example.com'),
+		]);
+		$this->emailValidator->method('isValid')->willReturn(true);
+
+		$this->jobList->expects($this->once())->method('add');
+
+		$service->send($form, $submission);
+	}
+
+	public function testValidateRecipientQuestionIdAllowsNull(): void {
+		$form = new Form();
+		$this->service->validateRecipientQuestionId($form, null);
+		$this->assertTrue(true);
+	}
+
+	public function testValidateRecipientQuestionIdRejectsNonInt(): void {
+		$form = new Form();
+		$this->expectException(\InvalidArgumentException::class);
+		$this->service->validateRecipientQuestionId($form, '7');
+	}
+
+	public function testValidateRecipientQuestionIdRejectsNotFoundQuestion(): void {
+		$form = new Form();
+		$this->questionMapper->method('findById')
+			->willThrowException(new DoesNotExistException(''));
+		$this->expectException(\InvalidArgumentException::class);
+		$this->service->validateRecipientQuestionId($form, 7);
+	}
+
+	public function testValidateRecipientQuestionIdRejectsMismatchedForm(): void {
+		$form = new Form();
+		$form->setId(1);
+
+		$question = new Question();
+		$question->setFormId(2);
+		$question->setOrder(1);
+		$question->setType(Constants::ANSWER_TYPE_SHORT);
+		$question->setExtraSettings(['validationType' => 'email']);
+
+		$this->questionMapper->method('findById')->willReturn($question);
+		$this->expectException(\InvalidArgumentException::class);
+		$this->service->validateRecipientQuestionId($form, 7);
+	}
+
+	public function testValidateRecipientQuestionIdRejectsDeletedQuestion(): void {
+		$form = new Form();
+		$form->setId(1);
+
+		$question = new Question();
+		$question->setFormId(1);
+		$question->setOrder(0);
+		$question->setType(Constants::ANSWER_TYPE_SHORT);
+		$question->setExtraSettings(['validationType' => 'email']);
+
+		$this->questionMapper->method('findById')->willReturn($question);
+		$this->expectException(\InvalidArgumentException::class);
+		$this->service->validateRecipientQuestionId($form, 7);
+	}
+
+	public function testValidateRecipientQuestionIdRejectsNonEmailQuestion(): void {
+		$form = new Form();
+		$form->setId(1);
+
+		$question = new Question();
+		$question->setFormId(1);
+		$question->setOrder(1);
+		$question->setType(Constants::ANSWER_TYPE_LONG);
+
+		$this->questionMapper->method('findById')->willReturn($question);
+		$this->expectException(\InvalidArgumentException::class);
+		$this->service->validateRecipientQuestionId($form, 7);
+	}
+
+	public function testValidateRecipientQuestionIdAllowsValidQuestion(): void {
+		$form = new Form();
+		$form->setId(1);
+
+		$question = new Question();
+		$question->setFormId(1);
+		$question->setOrder(1);
+		$question->setType(Constants::ANSWER_TYPE_SHORT);
+		$question->setExtraSettings(['validationType' => 'email']);
+
+		$this->questionMapper->method('findById')->willReturn($question);
+		$this->service->validateRecipientQuestionId($form, 7);
+		$this->assertTrue(true);
+	}
+}
diff --git a/tests/Unit/Service/FormsServiceTest.php b/tests/Unit/Service/FormsServiceTest.php
index 0ae0378de..a62f2b80a 100644
--- a/tests/Unit/Service/FormsServiceTest.php
+++ b/tests/Unit/Service/FormsServiceTest.php
@@ -44,6 +44,7 @@ function microtime(bool|float $asFloat = false) {
 use OCA\Forms\Db\SubmissionMapper;
 use OCA\Forms\Service\CirclesService;
 use OCA\Forms\Service\ConfigService;
+use OCA\Forms\Service\ConfirmationEmailService;
 use OCA\Forms\Service\FormsService;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\EventDispatcher\IEventDispatcher;
@@ -111,6 +112,9 @@ class FormsServiceTest extends TestCase {
 	/** @var LoggerInterface|MockObject */
 	private $logger;
 
+	/** @var ConfirmationEmailService|MockObject */
+	private $confirmationEmailService;
+
 	public function setUp(): void {
 		parent::setUp();
 		$this->activityManager = $this->createMock(ActivityManager::class);
@@ -121,6 +125,7 @@ public function setUp(): void {
 		$this->submissionMapper = $this->createMock(SubmissionMapper::class);
 		$this->configService = $this->createMock(ConfigService::class);
 		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->confirmationEmailService = $this->createMock(ConfirmationEmailService::class);
 		$this->groupManager = $this->createMock(IGroupManager::class);
 		$this->userManager = $this->createMock(IUserManager::class);
 		$this->secureRandom = $this->createMock(ISecureRandom::class);
@@ -159,10 +164,35 @@ public function setUp(): void {
 			$this->l10n,
 			$this->logger,
 			\OCP\Server::get(IEventDispatcher::class),
-			$this->logger,
+			$this->confirmationEmailService,
 		);
 	}
 
+	private function createFormsServiceWithEventDispatcher(IEventDispatcher $eventDispatcher): FormsService {
+		return $this->getMockBuilder(FormsService::class)
+			->onlyMethods(['getShares'])
+			->setConstructorArgs([
+				$this->createMock(IUserSession::class),
+				$this->activityManager,
+				$this->formMapper,
+				$this->optionMapper,
+				$this->questionMapper,
+				$this->shareMapper,
+				$this->submissionMapper,
+				$this->configService,
+				$this->groupManager,
+				$this->userManager,
+				$this->secureRandom,
+				$this->circlesService,
+				$this->storage,
+				$this->l10n,
+				$this->logger,
+				$eventDispatcher,
+				$this->confirmationEmailService,
+			])
+			->getMock();
+	}
+
 	public function testGenerateFormHash() {
 		$this->secureRandom->expects($this->once())
 			->method('generate')
@@ -256,6 +286,10 @@ public static function dataGetForm() {
 				'lockedUntil' => null,
 				'maxSubmissions' => null,
 				'isMaxSubmissionsReached' => false,
+				'confirmationEmailEnabled' => false,
+				'confirmationEmailSubject' => null,
+				'confirmationEmailBody' => null,
+				'confirmationEmailQuestionId' => null,
 			]]
 		];
 	}
@@ -473,6 +507,10 @@ public static function dataGetPublicForm() {
 				'lockedUntil' => null,
 				'maxSubmissions' => null,
 				'isMaxSubmissionsReached' => false,
+				'confirmationEmailEnabled' => false,
+				'confirmationEmailSubject' => null,
+				'confirmationEmailBody' => null,
+				'confirmationEmailQuestionId' => null,
 			]]
 		];
 	}
@@ -640,7 +678,7 @@ public function testGetPermissions_NotLoggedIn() {
 			$this->l10n,
 			$this->logger,
 			\OCP\Server::get(IEventDispatcher::class),
-			$this->logger,
+			$this->confirmationEmailService,
 		);
 
 		$form = new Form();
@@ -865,7 +903,7 @@ public function testPublicCanSubmit() {
 			$this->l10n,
 			$this->logger,
 			\OCP\Server::get(IEventDispatcher::class),
-			$this->logger,
+			$this->confirmationEmailService,
 		);
 
 		$this->assertEquals(true, $formsService->canSubmit($form));
@@ -973,7 +1011,7 @@ public function testHasUserAccess_NotLoggedIn() {
 			$this->l10n,
 			$this->logger,
 			\OCP\Server::get(IEventDispatcher::class),
-			$this->logger,
+			$this->confirmationEmailService,
 		);
 
 		$form = new Form();
@@ -1196,7 +1234,7 @@ public function testNotifyNewSubmission($shares, $shareNotifications) {
 				$this->l10n,
 				$this->logger,
 				$eventDispatcher,
-				$this->logger,
+				$this->confirmationEmailService,
 			])
 			->getMock();
 
@@ -1213,6 +1251,8 @@ public function testNotifyNewSubmission($shares, $shareNotifications) {
 
 		$eventDispatcher->expects($this->exactly(1))->method('dispatchTyped')->withAnyParameters();
 
+		$this->confirmationEmailService->expects($this->once())->method('send')->with($form, $submission);
+
 		$formsService->notifyNewSubmission($form, $submission);
 	}
 
@@ -1553,9 +1593,10 @@ public function testGetQuestionsHandlesDoesNotExistException(): void {
 		$this->assertEmpty($result);
 	}
 
-	private function createQuestionEntity(array $data): Question {
+	private function createQuestionEntity(array $data): MockObject {
 		$questionEntity = $this->createMock(Question::class);
 		$questionEntity->method('read')->willReturn($data);
 		return $questionEntity;
 	}
+
 }