diff --git a/apps/files/composer/composer/autoload_classmap.php b/apps/files/composer/composer/autoload_classmap.php
index 3fd82c774c240..3a778805d545b 100644
--- a/apps/files/composer/composer/autoload_classmap.php
+++ b/apps/files/composer/composer/autoload_classmap.php
@@ -61,6 +61,7 @@
     'OCA\\Files\\Controller\\DirectEditingViewController' => $baseDir . '/../lib/Controller/DirectEditingViewController.php',
     'OCA\\Files\\Controller\\FilenamesController' => $baseDir . '/../lib/Controller/FilenamesController.php',
     'OCA\\Files\\Controller\\OpenLocalEditorController' => $baseDir . '/../lib/Controller/OpenLocalEditorController.php',
+    'OCA\\Files\\Controller\\OpenedController' => $baseDir . '/../lib/Controller/OpenedController.php',
     'OCA\\Files\\Controller\\TemplateController' => $baseDir . '/../lib/Controller/TemplateController.php',
     'OCA\\Files\\Controller\\TransferOwnershipController' => $baseDir . '/../lib/Controller/TransferOwnershipController.php',
     'OCA\\Files\\Controller\\ViewController' => $baseDir . '/../lib/Controller/ViewController.php',
diff --git a/apps/files/composer/composer/autoload_static.php b/apps/files/composer/composer/autoload_static.php
index 5c8eb91c4c2e5..c92f1b55ff3df 100644
--- a/apps/files/composer/composer/autoload_static.php
+++ b/apps/files/composer/composer/autoload_static.php
@@ -76,6 +76,7 @@ class ComposerStaticInitFiles
         'OCA\\Files\\Controller\\DirectEditingViewController' => __DIR__ . '/..' . '/../lib/Controller/DirectEditingViewController.php',
         'OCA\\Files\\Controller\\FilenamesController' => __DIR__ . '/..' . '/../lib/Controller/FilenamesController.php',
         'OCA\\Files\\Controller\\OpenLocalEditorController' => __DIR__ . '/..' . '/../lib/Controller/OpenLocalEditorController.php',
+        'OCA\\Files\\Controller\\OpenedController' => __DIR__ . '/..' . '/../lib/Controller/OpenedController.php',
         'OCA\\Files\\Controller\\TemplateController' => __DIR__ . '/..' . '/../lib/Controller/TemplateController.php',
         'OCA\\Files\\Controller\\TransferOwnershipController' => __DIR__ . '/..' . '/../lib/Controller/TransferOwnershipController.php',
         'OCA\\Files\\Controller\\ViewController' => __DIR__ . '/..' . '/../lib/Controller/ViewController.php',
diff --git a/apps/files/lib/Controller/OpenedController.php b/apps/files/lib/Controller/OpenedController.php
new file mode 100644
index 0000000000000..2b68b342216e6
--- /dev/null
+++ b/apps/files/lib/Controller/OpenedController.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files\Controller;
+
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\Attribute\ApiRoute;
+use OCP\AppFramework\Http\Attribute\NoAdminRequired;
+use OCP\AppFramework\Http\Attribute\UserRateLimit;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\OCS\OCSNotFoundException;
+use OCP\AppFramework\OCSController;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\Node\NodeOpenedEvent;
+use OCP\Files\IRootFolder;
+use OCP\IL10N;
+use OCP\IRequest;
+use OCP\IUser;
+
+final class OpenedController extends OCSController {
+	public function __construct(
+		string $appName,
+		IRequest $request,
+		private readonly IRootFolder $rootFolder,
+		private readonly IEventDispatcher $eventDispatcher,
+		private readonly IL10N $l10n,
+	) {
+		parent::__construct($appName, $request);
+	}
+
+	/**
+	 * Report that the current user opened a file or folder
+	 *
+	 * Clients call this when the user actually opens a node, not when they
+	 * read its content (sync, previews, downloads). Apps can listen to it to
+	 * know what the user works with. It is for statistics only: clients send it
+	 * when they choose to, so it must not be relied on for access or auditing.
+	 *
+	 * @param int $fileId ID of the opened file or folder
+	 *
+	 * @return DataResponse<Http::STATUS_OK, list<empty>, array{}>
+	 * @throws OCSNotFoundException The file or folder was not found
+	 *
+	 * 200: Open reported
+	 */
+	#[NoAdminRequired]
+	#[UserRateLimit(limit: 100, period: 60)]
+	#[ApiRoute(verb: 'POST', url: '/api/v1/opened')]
+	public function opened(IUser $user, int $fileId): DataResponse {
+		$node = $this->rootFolder->getUserFolder($user->getUID())->getFirstNodeById($fileId);
+
+		// Also a 404 if the node is not readable, to not leak its existence
+		if ($node === null || !$node->isReadable()) {
+			throw new OCSNotFoundException($this->l10n->t('The file cannot be found'));
+		}
+
+		$this->eventDispatcher->dispatchTyped(new NodeOpenedEvent($node, $user));
+		return new DataResponse([]);
+	}
+}
diff --git a/apps/files/openapi.json b/apps/files/openapi.json
index 808a0e07a41a1..f387f34931655 100644
--- a/apps/files/openapi.json
+++ b/apps/files/openapi.json
@@ -2906,6 +2906,142 @@
                     }
                 }
             }
+        },
+        "/ocs/v2.php/apps/files/api/v1/opened": {
+            "post": {
+                "operationId": "opened-opened",
+                "summary": "Report that the current user opened a file or folder",
+                "description": "Clients call this when the user actually opens a node, not when they read its content (sync, previews, downloads). Apps can listen to it to know what the user works with. It is for statistics only: clients send it when they choose to, so it must not be relied on for access or auditing.",
+                "tags": [
+                    "opened"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "requestBody": {
+                    "required": true,
+                    "content": {
+                        "application/json": {
+                            "schema": {
+                                "type": "object",
+                                "required": [
+                                    "fileId"
+                                ],
+                                "properties": {
+                                    "fileId": {
+                                        "type": "integer",
+                                        "format": "int64",
+                                        "description": "ID of the opened file or folder"
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "parameters": [
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Open reported",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "The file or folder was not found",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
         }
     },
     "tags": []
diff --git a/apps/files/tests/Controller/OpenedControllerTest.php b/apps/files/tests/Controller/OpenedControllerTest.php
new file mode 100644
index 0000000000000..b1bf84a1833b1
--- /dev/null
+++ b/apps/files/tests/Controller/OpenedControllerTest.php
@@ -0,0 +1,82 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files\Tests\Controller;
+
+use OCA\Files\Controller\OpenedController;
+use OCP\AppFramework\OCS\OCSNotFoundException;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\Node\NodeOpenedEvent;
+use OCP\Files\File;
+use OCP\Files\IRootFolder;
+use OCP\Files\IUserFolder;
+use OCP\IL10N;
+use OCP\IRequest;
+use OCP\IUser;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class OpenedControllerTest extends TestCase {
+	private IUserFolder&MockObject $userFolder;
+	private IEventDispatcher&MockObject $eventDispatcher;
+	private IUser&MockObject $user;
+	private OpenedController $controller;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->user = $this->createMock(IUser::class);
+		$this->user->method('getUID')->willReturn('alice');
+
+		$this->userFolder = $this->createMock(IUserFolder::class);
+		$rootFolder = $this->createMock(IRootFolder::class);
+		$rootFolder->method('getUserFolder')->with('alice')->willReturn($this->userFolder);
+
+		$this->eventDispatcher = $this->createMock(IEventDispatcher::class);
+
+		$this->controller = new OpenedController(
+			'files',
+			$this->createMock(IRequest::class),
+			$rootFolder,
+			$this->eventDispatcher,
+			$this->createMock(IL10N::class),
+		);
+	}
+
+	public function testDispatchesEvent(): void {
+		$file = $this->createMock(File::class);
+		$file->method('isReadable')->willReturn(true);
+		$this->userFolder->method('getFirstNodeById')->with(42)->willReturn($file);
+
+		$this->eventDispatcher->expects($this->once())
+			->method('dispatchTyped')
+			->with($this->callback(fn (NodeOpenedEvent $event): bool
+				=> $event->getNode() === $file && $event->getUser() === $this->user));
+
+		$this->controller->opened($this->user, 42);
+	}
+
+	public function testNotFound(): void {
+		$this->userFolder->method('getFirstNodeById')->with(42)->willReturn(null);
+		$this->eventDispatcher->expects($this->never())->method('dispatchTyped');
+
+		$this->expectException(OCSNotFoundException::class);
+		$this->controller->opened($this->user, 42);
+	}
+
+	public function testNotReadable(): void {
+		$file = $this->createMock(File::class);
+		$file->method('isReadable')->willReturn(false);
+		$this->userFolder->method('getFirstNodeById')->with(42)->willReturn($file);
+		$this->eventDispatcher->expects($this->never())->method('dispatchTyped');
+
+		$this->expectException(OCSNotFoundException::class);
+		$this->controller->opened($this->user, 42);
+	}
+}
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index b3b5b63fb3a1e..6010d5580da18 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -545,6 +545,7 @@
     'OCP\\Files\\Events\\Node\\NodeCopiedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeCopiedEvent.php',
     'OCP\\Files\\Events\\Node\\NodeCreatedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeCreatedEvent.php',
     'OCP\\Files\\Events\\Node\\NodeDeletedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeDeletedEvent.php',
+    'OCP\\Files\\Events\\Node\\NodeOpenedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeOpenedEvent.php',
     'OCP\\Files\\Events\\Node\\NodeRenamedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeRenamedEvent.php',
     'OCP\\Files\\Events\\Node\\NodeTouchedEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeTouchedEvent.php',
     'OCP\\Files\\Events\\Node\\NodeWrittenEvent' => $baseDir . '/lib/public/Files/Events/Node/NodeWrittenEvent.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 35c872fd7527d..a872edba351e7 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -586,6 +586,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Files\\Events\\Node\\NodeCopiedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeCopiedEvent.php',
         'OCP\\Files\\Events\\Node\\NodeCreatedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeCreatedEvent.php',
         'OCP\\Files\\Events\\Node\\NodeDeletedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeDeletedEvent.php',
+        'OCP\\Files\\Events\\Node\\NodeOpenedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeOpenedEvent.php',
         'OCP\\Files\\Events\\Node\\NodeRenamedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeRenamedEvent.php',
         'OCP\\Files\\Events\\Node\\NodeTouchedEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeTouchedEvent.php',
         'OCP\\Files\\Events\\Node\\NodeWrittenEvent' => __DIR__ . '/../../..' . '/lib/public/Files/Events/Node/NodeWrittenEvent.php',
diff --git a/lib/public/Files/Events/Node/NodeOpenedEvent.php b/lib/public/Files/Events/Node/NodeOpenedEvent.php
new file mode 100644
index 0000000000000..41d9db9d255f3
--- /dev/null
+++ b/lib/public/Files/Events/Node/NodeOpenedEvent.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Files\Events\Node;
+
+use OCP\AppFramework\Attribute\Listenable;
+use OCP\EventDispatcher\JsonSerializer;
+use OCP\Files\Node;
+use OCP\IUser;
+
+/**
+ * A user opened a node in a client, as reported by that client.
+ *
+ * Unlike {@see BeforeNodeReadEvent}, this is not dispatched when the content
+ * is read (sync, previews, downloads) but only when a client says the user
+ * actually opened it.
+ *
+ * It is meant for statistics only, like recommending the files a user works
+ * with. Clients report it when they choose to, so it can be missing, repeated
+ * or sent for a node the user never looked at. Never use it for permissions,
+ * access control, auditing, or anything else that has to be reliable.
+ *
+ * @since 36.0.0
+ */
+#[Listenable(since: '36.0.0')]
+class NodeOpenedEvent extends AbstractNodeEvent {
+	/**
+	 * @since 36.0.0
+	 */
+	public function __construct(
+		Node $node,
+		private IUser $user,
+	) {
+		parent::__construct($node);
+	}
+
+	/**
+	 * The user who opened the node
+	 *
+	 * @since 36.0.0
+	 */
+	public function getUser(): IUser {
+		return $this->user;
+	}
+
+	/**
+	 * @since 36.0.0
+	 */
+	#[\Override]
+	public function getWebhookSerializable(): array {
+		return [
+			...parent::getWebhookSerializable(),
+			'user' => JsonSerializer::serializeUser($this->user),
+		];
+	}
+}
diff --git a/openapi.json b/openapi.json
index 78f138e0ec809..6c26d3ac0f2ce 100644
--- a/openapi.json
+++ b/openapi.json
@@ -26755,6 +26755,142 @@
                 }
             }
         },
+        "/ocs/v2.php/apps/files/api/v1/opened": {
+            "post": {
+                "operationId": "files-opened-opened",
+                "summary": "Report that the current user opened a file or folder",
+                "description": "Clients call this when the user actually opens a node, not when they read its content (sync, previews, downloads). Apps can listen to it to know what the user works with. It is for statistics only: clients send it when they choose to, so it must not be relied on for access or auditing.",
+                "tags": [
+                    "files/opened"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "requestBody": {
+                    "required": true,
+                    "content": {
+                        "application/json": {
+                            "schema": {
+                                "type": "object",
+                                "required": [
+                                    "fileId"
+                                ],
+                                "properties": {
+                                    "fileId": {
+                                        "type": "integer",
+                                        "format": "int64",
+                                        "description": "ID of the opened file or folder"
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "parameters": [
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Open reported",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "The file or folder was not found",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
         "/ocs/v2.php/apps/files_external/api/v1/mounts": {
             "get": {
                 "operationId": "files_external-api-get-user-mounts",