diff --git a/core/src/types/teams.d.ts b/core/src/types/teams.d.ts
new file mode 100644
index 0000000000000..55a8d3f18fe22
--- /dev/null
+++ b/core/src/types/teams.d.ts
@@ -0,0 +1,76 @@
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+export interface TeamFolder {
+	id: number
+	mountPoint: string
+	quota: number | null
+}
+
+export interface SharedResourceProvider {
+	id: string
+	name: string
+}
+
+export interface SharedResource {
+	id: string | number
+	label: string
+	url: string
+	iconSvg?: string
+	iconURL?: string
+	iconEmoji?: string
+	provider: SharedResourceProvider
+}
+
+export interface TeamAppAction {
+	id: string
+	label: string
+	icon?: string
+	prompt?: { title: string, value?: string }
+	confirm?: { title: string, message: string }
+	resourcePicker?: TeamAppResourcePickerOptions
+}
+
+export interface TeamAppEntry {
+	id: string
+	label: string
+	icon?: string
+	iconSvg?: string
+	iconEmoji?: string
+	href?: string
+	legacyIds?: string[]
+	actions?: TeamAppAction[]
+	viewData?: Record<string, unknown>
+}
+
+export interface TeamAppNavigation {
+	entries: TeamAppEntry[]
+	actions?: TeamAppAction[]
+	resourceKeys?: Array<{ providerId: string, resourceId: string }>
+}
+
+export interface TeamAppActionResult {
+	navigationEntryIds?: string[]
+	open?: string
+}
+
+export interface TeamAppResource extends Pick<TeamAppEntry, 'id' | 'label' | 'icon' | 'iconSvg' | 'iconEmoji'> {
+	description?: string
+}
+
+export interface TeamAppResourcePickerOptions {
+	title: string
+	resources: TeamAppResource[]
+	selectedIds?: string[]
+}
+
+export interface TeamAppContext {
+	teamId: string
+	signal: AbortSignal
+}
+
+export interface TeamAppView {
+	mount: (element: HTMLElement, context: TeamAppContext, entry: TeamAppEntry) => Promise<() => void>
+}
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index b3b5b63fb3a1e..50fb602e9bab9 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -1074,10 +1074,21 @@
     'OCP\\TaskProcessing\\TaskTypes\\TextToTextSummary' => $baseDir . '/lib/public/TaskProcessing/TaskTypes/TextToTextSummary.php',
     'OCP\\TaskProcessing\\TaskTypes\\TextToTextTopics' => $baseDir . '/lib/public/TaskProcessing/TaskTypes/TextToTextTopics.php',
     'OCP\\TaskProcessing\\TaskTypes\\TextToTextTranslate' => $baseDir . '/lib/public/TaskProcessing/TaskTypes/TextToTextTranslate.php',
+    'OCP\\Teams\\ITeamAppProvider' => $baseDir . '/lib/public/Teams/ITeamAppProvider.php',
     'OCP\\Teams\\ITeamFolderProvider' => $baseDir . '/lib/public/Teams/ITeamFolderProvider.php',
     'OCP\\Teams\\ITeamManager' => $baseDir . '/lib/public/Teams/ITeamManager.php',
     'OCP\\Teams\\ITeamResourceProvider' => $baseDir . '/lib/public/Teams/ITeamResourceProvider.php',
     'OCP\\Teams\\Team' => $baseDir . '/lib/public/Teams/Team.php',
+    'OCP\\Teams\\TeamAppAction' => $baseDir . '/lib/public/Teams/TeamAppAction.php',
+    'OCP\\Teams\\TeamAppActionConfirmation' => $baseDir . '/lib/public/Teams/TeamAppActionConfirmation.php',
+    'OCP\\Teams\\TeamAppActionPrompt' => $baseDir . '/lib/public/Teams/TeamAppActionPrompt.php',
+    'OCP\\Teams\\TeamAppActionResult' => $baseDir . '/lib/public/Teams/TeamAppActionResult.php',
+    'OCP\\Teams\\TeamAppEntry' => $baseDir . '/lib/public/Teams/TeamAppEntry.php',
+    'OCP\\Teams\\TeamAppNavigation' => $baseDir . '/lib/public/Teams/TeamAppNavigation.php',
+    'OCP\\Teams\\TeamAppResource' => $baseDir . '/lib/public/Teams/TeamAppResource.php',
+    'OCP\\Teams\\TeamAppResourceKey' => $baseDir . '/lib/public/Teams/TeamAppResourceKey.php',
+    'OCP\\Teams\\TeamAppResourcePicker' => $baseDir . '/lib/public/Teams/TeamAppResourcePicker.php',
+    'OCP\\Teams\\TeamAppRouteAlias' => $baseDir . '/lib/public/Teams/TeamAppRouteAlias.php',
     'OCP\\Teams\\TeamFolder' => $baseDir . '/lib/public/Teams/TeamFolder.php',
     'OCP\\Teams\\TeamResource' => $baseDir . '/lib/public/Teams/TeamResource.php',
     'OCP\\Template' => $baseDir . '/lib/public/Template.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 35c872fd7527d..cde62bc899be4 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -1115,10 +1115,21 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\TaskProcessing\\TaskTypes\\TextToTextSummary' => __DIR__ . '/../../..' . '/lib/public/TaskProcessing/TaskTypes/TextToTextSummary.php',
         'OCP\\TaskProcessing\\TaskTypes\\TextToTextTopics' => __DIR__ . '/../../..' . '/lib/public/TaskProcessing/TaskTypes/TextToTextTopics.php',
         'OCP\\TaskProcessing\\TaskTypes\\TextToTextTranslate' => __DIR__ . '/../../..' . '/lib/public/TaskProcessing/TaskTypes/TextToTextTranslate.php',
+        'OCP\\Teams\\ITeamAppProvider' => __DIR__ . '/../../..' . '/lib/public/Teams/ITeamAppProvider.php',
         'OCP\\Teams\\ITeamFolderProvider' => __DIR__ . '/../../..' . '/lib/public/Teams/ITeamFolderProvider.php',
         'OCP\\Teams\\ITeamManager' => __DIR__ . '/../../..' . '/lib/public/Teams/ITeamManager.php',
         'OCP\\Teams\\ITeamResourceProvider' => __DIR__ . '/../../..' . '/lib/public/Teams/ITeamResourceProvider.php',
         'OCP\\Teams\\Team' => __DIR__ . '/../../..' . '/lib/public/Teams/Team.php',
+        'OCP\\Teams\\TeamAppAction' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppAction.php',
+        'OCP\\Teams\\TeamAppActionConfirmation' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppActionConfirmation.php',
+        'OCP\\Teams\\TeamAppActionPrompt' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppActionPrompt.php',
+        'OCP\\Teams\\TeamAppActionResult' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppActionResult.php',
+        'OCP\\Teams\\TeamAppEntry' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppEntry.php',
+        'OCP\\Teams\\TeamAppNavigation' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppNavigation.php',
+        'OCP\\Teams\\TeamAppResource' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppResource.php',
+        'OCP\\Teams\\TeamAppResourceKey' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppResourceKey.php',
+        'OCP\\Teams\\TeamAppResourcePicker' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppResourcePicker.php',
+        'OCP\\Teams\\TeamAppRouteAlias' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamAppRouteAlias.php',
         'OCP\\Teams\\TeamFolder' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamFolder.php',
         'OCP\\Teams\\TeamResource' => __DIR__ . '/../../..' . '/lib/public/Teams/TeamResource.php',
         'OCP\\Template' => __DIR__ . '/../../..' . '/lib/public/Template.php',
diff --git a/lib/private/AppFramework/Bootstrap/RegistrationContext.php b/lib/private/AppFramework/Bootstrap/RegistrationContext.php
index f86890441243b..2b524b610ac46 100644
--- a/lib/private/AppFramework/Bootstrap/RegistrationContext.php
+++ b/lib/private/AppFramework/Bootstrap/RegistrationContext.php
@@ -45,6 +45,7 @@
 use OCP\SystemReport\ISystemReportSection;
 use OCP\Talk\ITalkBackend;
 use OCP\TaskProcessing\ITaskType;
+use OCP\Teams\ITeamAppProvider;
 use OCP\Teams\ITeamResourceProvider;
 use OCP\TextProcessing\IProvider as ITextProcessingProvider;
 use OCP\Translation\ITranslationProvider;
@@ -163,6 +164,9 @@ class RegistrationContext {
 	/** @var ServiceRegistration<ITeamResourceProvider>[] */
 	private array $teamResourceProviders = [];
 
+	/** @var ServiceRegistration<ITeamAppProvider>[] */
+	private array $teamAppProviders = [];
+
 	/** @var ServiceRegistration<\OCP\TaskProcessing\IProvider>[] */
 	private array $taskProcessingProviders = [];
 
@@ -422,6 +426,11 @@ public function registerTeamResourceProvider(string $class) : void {
 				);
 			}
 
+			#[\Override]
+			public function registerTeamAppProvider(string $class): void {
+				$this->context->registerTeamAppProvider($this->appId, $class);
+			}
+
 			#[\Override]
 			public function registerCalendarRoomBackend(string $class): void {
 				$this->context->registerCalendarRoomBackend(
@@ -682,6 +691,13 @@ public function registerTeamResourceProvider(string $appId, string $class) {
 		);
 	}
 
+	/**
+	 * @psalm-param class-string<ITeamAppProvider> $class
+	 */
+	public function registerTeamAppProvider(string $appId, string $class): void {
+		$this->teamAppProviders[] = new ServiceRegistration($appId, $class);
+	}
+
 	/**
 	 * @psalm-param class-string<IUserMigrator> $migratorClass
 	 */
@@ -1117,6 +1133,13 @@ public function getTeamResourceProviders(): array {
 		return $this->teamResourceProviders;
 	}
 
+	/**
+	 * @return ServiceRegistration<ITeamAppProvider>[]
+	 */
+	public function getTeamAppProviders(): array {
+		return $this->teamAppProviders;
+	}
+
 	/**
 	 * @return ServiceRegistration<IDeclarativeSettingsForm>[]
 	 */
diff --git a/lib/public/AppFramework/Bootstrap/IRegistrationContext.php b/lib/public/AppFramework/Bootstrap/IRegistrationContext.php
index 598bbb5fdae73..a8edae446ed54 100644
--- a/lib/public/AppFramework/Bootstrap/IRegistrationContext.php
+++ b/lib/public/AppFramework/Bootstrap/IRegistrationContext.php
@@ -362,6 +362,14 @@ public function registerCalendarRoomBackend(string $class): void;
 	 */
 	public function registerTeamResourceProvider(string $class): void;
 
+	/**
+	 * Register app-owned navigation and embedded views for the Teams page.
+	 *
+	 * @param class-string<\OCP\Teams\ITeamAppProvider> $class
+	 * @since 36.0.0
+	 */
+	public function registerTeamAppProvider(string $class): void;
+
 	/**
 	 * Register an implementation of \OCP\UserMigration\IMigrator that
 	 * will handle the implementation of a migrator
diff --git a/lib/public/Teams/ITeamAppProvider.php b/lib/public/Teams/ITeamAppProvider.php
new file mode 100644
index 0000000000000..1cffd79914254
--- /dev/null
+++ b/lib/public/Teams/ITeamAppProvider.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 OCP\Teams;
+
+/**
+ * App-owned navigation and optional embedded views on the Teams page.
+ *
+ * Register the implementation with IRegistrationContext::registerTeamAppProvider().
+ *
+ * @since 36.0.0
+ */
+interface ITeamAppProvider {
+	/**
+	 * Return the owning app ID.
+	 *
+	 * @since 36.0.0
+	 */
+	public function getId(): string;
+
+	/**
+	 * Prepare initial state/styles and return an optional embedded-view module URL.
+	 *
+	 * @since 36.0.0
+	 */
+	public function load(): ?string;
+
+	/** @since 36.0.0 */
+	public function getOrder(): int;
+
+	/**
+	 * Return alternate routes and the route parameter identifying an entry.
+	 *
+	 * @return list<TeamAppRouteAlias>
+	 * @since 36.0.0
+	 */
+	public function getRouteAliases(): array;
+
+	/**
+	 * Return navigation entries, available actions and shared resources represented by the entries.
+	 *
+	 * @param array{teamId: string, teamName: string, userId: string, isAdmin: bool, folder: ?TeamFolder, resources: list<TeamResource>, navigationEntryIds: list<string>, saveNavigationEntryIds: callable} $context
+	 * @return TeamAppNavigation Entries and optional actions and resource keys for this team.
+	 * @since 36.0.0
+	 */
+	public function getNavigation(array $context): TeamAppNavigation;
+
+	/**
+	 * Execute an app action and return optional replacement navigation entry IDs and an entry ID to open.
+	 *
+	 * @param array{teamId: string, teamName: string, userId: string, isAdmin: bool, folder: ?TeamFolder, resources: list<TeamResource>, navigationEntryIds: list<string>, saveNavigationEntryIds: callable} $context
+	 * @param array<string, mixed> $parameters
+	 * @return TeamAppActionResult Omitted keys leave the current navigation and open entry unchanged.
+	 * @since 36.0.0
+	 */
+	public function executeAction(array $context, string $actionId, array $parameters): TeamAppActionResult;
+}
diff --git a/lib/public/Teams/TeamAppAction.php b/lib/public/Teams/TeamAppAction.php
new file mode 100644
index 0000000000000..2eeb17d6591d4
--- /dev/null
+++ b/lib/public/Teams/TeamAppAction.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * An available app command with optional input or confirmation dialogs.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppAction implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $id,
+		public readonly string $label,
+		public readonly ?string $icon = null,
+		public readonly ?TeamAppActionPrompt $prompt = null,
+		public readonly ?TeamAppActionConfirmation $confirm = null,
+		public readonly ?TeamAppResourcePicker $resourcePicker = null,
+	) {
+	}
+
+	/**
+	 * @return array<string, string|TeamAppActionPrompt|TeamAppActionConfirmation|TeamAppResourcePicker>
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppActionConfirmation.php b/lib/public/Teams/TeamAppActionConfirmation.php
new file mode 100644
index 0000000000000..e94ffc4784fa4
--- /dev/null
+++ b/lib/public/Teams/TeamAppActionConfirmation.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * A confirmation dialog displayed before executing an app action.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppActionConfirmation implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $title,
+		public readonly string $message,
+	) {
+	}
+
+	/**
+	 * @return array{title: string, message: string}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return ['title' => $this->title, 'message' => $this->message];
+	}
+}
diff --git a/lib/public/Teams/TeamAppActionPrompt.php b/lib/public/Teams/TeamAppActionPrompt.php
new file mode 100644
index 0000000000000..8ea7838706777
--- /dev/null
+++ b/lib/public/Teams/TeamAppActionPrompt.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * A text prompt displayed before executing an app action.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppActionPrompt implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $title,
+		public readonly ?string $value = null,
+	) {
+	}
+
+	/**
+	 * @return array{title: string, value?: string}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(['title' => $this->title, 'value' => $this->value], static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppActionResult.php b/lib/public/Teams/TeamAppActionResult.php
new file mode 100644
index 0000000000000..dac5e09225833
--- /dev/null
+++ b/lib/public/Teams/TeamAppActionResult.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * Optional replacement navigation entry IDs and the entry to open after an action.
+ * Null fields leave the current navigation and open entry unchanged.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppActionResult implements \JsonSerializable {
+	/**
+	 * @param list<string>|null $navigationEntryIds
+	 * @since 36.0.0
+	 */
+	public function __construct(
+		public readonly ?array $navigationEntryIds = null,
+		public readonly ?string $open = null,
+	) {
+	}
+
+	/**
+	 * @return array{navigationEntryIds?: list<string>, open?: string}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppEntry.php b/lib/public/Teams/TeamAppEntry.php
new file mode 100644
index 0000000000000..6b65c222af628
--- /dev/null
+++ b/lib/public/Teams/TeamAppEntry.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * A navigation entry linking to a resource or an embedded app view.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppEntry implements \JsonSerializable {
+	/**
+	 * @param list<string>|null $legacyIds
+	 * @param list<TeamAppAction>|null $actions
+	 * @param array<string, mixed>|null $viewData
+	 * @since 36.0.0
+	 */
+	public function __construct(
+		public readonly string $id,
+		public readonly string $label,
+		public readonly ?string $icon = null,
+		public readonly ?string $iconSvg = null,
+		public readonly ?string $iconEmoji = null,
+		public readonly ?string $href = null,
+		public readonly ?array $legacyIds = null,
+		public readonly ?array $actions = null,
+		public readonly ?array $viewData = null,
+	) {
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppNavigation.php b/lib/public/Teams/TeamAppNavigation.php
new file mode 100644
index 0000000000000..18d38092ec924
--- /dev/null
+++ b/lib/public/Teams/TeamAppNavigation.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * Navigation entries, actions and represented shared resources for a team.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppNavigation implements \JsonSerializable {
+	/**
+	 * @param list<TeamAppEntry> $entries
+	 * @param list<TeamAppAction>|null $actions
+	 * @param list<TeamAppResourceKey>|null $resourceKeys
+	 * @since 36.0.0
+	 */
+	public function __construct(
+		public readonly array $entries,
+		public readonly ?array $actions = null,
+		public readonly ?array $resourceKeys = null,
+	) {
+	}
+
+	/**
+	 * @return array{entries: list<TeamAppEntry>, actions?: list<TeamAppAction>, resourceKeys?: list<TeamAppResourceKey>}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppResource.php b/lib/public/Teams/TeamAppResource.php
new file mode 100644
index 0000000000000..73c518a640a2a
--- /dev/null
+++ b/lib/public/Teams/TeamAppResource.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * An app resource available for selection in a resource picker.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppResource implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $id,
+		public readonly string $label,
+		public readonly ?string $description = null,
+		public readonly ?string $icon = null,
+		public readonly ?string $iconSvg = null,
+		public readonly ?string $iconEmoji = null,
+	) {
+	}
+
+	/**
+	 * @return array<string, string>
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppResourceKey.php b/lib/public/Teams/TeamAppResourceKey.php
new file mode 100644
index 0000000000000..f9d3c710f5371
--- /dev/null
+++ b/lib/public/Teams/TeamAppResourceKey.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * Identifies a shared resource already represented by an app entry.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppResourceKey implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $providerId,
+		public readonly string $resourceId,
+	) {
+	}
+
+	/**
+	 * @return array{providerId: string, resourceId: string}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return ['providerId' => $this->providerId, 'resourceId' => $this->resourceId];
+	}
+}
diff --git a/lib/public/Teams/TeamAppResourcePicker.php b/lib/public/Teams/TeamAppResourcePicker.php
new file mode 100644
index 0000000000000..f3d284080b954
--- /dev/null
+++ b/lib/public/Teams/TeamAppResourcePicker.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * A resource selection dialog displayed before executing an app action.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppResourcePicker implements \JsonSerializable {
+	/**
+	 * @param list<TeamAppResource> $resources
+	 * @param list<string>|null $selectedIds
+	 * @since 36.0.0
+	 */
+	public function __construct(
+		public readonly string $title,
+		public readonly array $resources,
+		public readonly ?array $selectedIds = null,
+	) {
+	}
+
+	/**
+	 * @return array{title: string, resources: list<TeamAppResource>, selectedIds?: list<string>}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_filter(get_object_vars($this), static fn ($value): bool => $value !== null);
+	}
+}
diff --git a/lib/public/Teams/TeamAppRouteAlias.php b/lib/public/Teams/TeamAppRouteAlias.php
new file mode 100644
index 0000000000000..c016153ebff08
--- /dev/null
+++ b/lib/public/Teams/TeamAppRouteAlias.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Teams;
+
+/**
+ * An alternate route and its parameter identifying a Teams app entry.
+ *
+ * @since 36.0.0
+ */
+final class TeamAppRouteAlias implements \JsonSerializable {
+	/** @since 36.0.0 */
+	public function __construct(
+		public readonly string $path,
+		public readonly string $entryParam,
+	) {
+	}
+
+	/**
+	 * @return array{path: string, entryParam: string}
+	 * @since 36.0.0
+	 */
+	public function jsonSerialize(): array {
+		return ['path' => $this->path, 'entryParam' => $this->entryParam];
+	}
+}
diff --git a/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php b/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php
index a3f87e7078edc..a34eee0183558 100644
--- a/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php
+++ b/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php
@@ -15,6 +15,7 @@
 use OC\Core\Middleware\TwoFactorMiddleware;
 use OCP\AppFramework\App;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Teams\ITeamAppProvider;
 use Psr\Log\LoggerInterface;
 use Test\TestCase;
 
@@ -146,6 +147,17 @@ public function testRegisterUserMigrator(): void {
 		);
 	}
 
+	public function testRegisterTeamAppProvider(): void {
+		$this->context->for('text')->registerTeamAppProvider(ITeamAppProvider::class);
+		$this->context->for('whiteboard')->registerTeamAppProvider(ITeamAppProvider::class);
+
+		$this->assertEquals([
+			new ServiceRegistration('text', ITeamAppProvider::class),
+			new ServiceRegistration('whiteboard', ITeamAppProvider::class),
+		], $this->context->getTeamAppProviders());
+		$this->assertSame([], $this->context->getTeamResourceProviders());
+	}
+
 	public static function dataProvider_TrueFalse(): array {
 		return[
 			[true],
diff --git a/tests/lib/Teams/TeamAppDataTest.php b/tests/lib/Teams/TeamAppDataTest.php
new file mode 100644
index 0000000000000..a37dacc7a30cc
--- /dev/null
+++ b/tests/lib/Teams/TeamAppDataTest.php
@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace Test\Teams;
+
+use OCP\Teams\TeamAppAction;
+use OCP\Teams\TeamAppActionConfirmation;
+use OCP\Teams\TeamAppActionPrompt;
+use OCP\Teams\TeamAppActionResult;
+use OCP\Teams\TeamAppEntry;
+use OCP\Teams\TeamAppNavigation;
+use OCP\Teams\TeamAppResource;
+use OCP\Teams\TeamAppResourceKey;
+use OCP\Teams\TeamAppResourcePicker;
+use OCP\Teams\TeamAppRouteAlias;
+use Test\TestCase;
+
+class TeamAppDataTest extends TestCase {
+	public function testSerializesRouteAlias(): void {
+		$alias = new TeamAppRouteAlias('page/:fileId', 'fileId');
+
+		$this->assertSame('page/:fileId', $alias->path);
+		$this->assertSame('fileId', $alias->entryParam);
+		$this->assertSame(['path' => 'page/:fileId', 'entryParam' => 'fileId'], $alias->jsonSerialize());
+	}
+
+	public function testSerializesNestedNavigation(): void {
+		$prompt = new TeamAppActionPrompt('Name', '');
+		$confirmation = new TeamAppActionConfirmation('Delete', 'Delete this item?');
+		$resource = new TeamAppResource('42', 'Board', '/Board.whiteboard', 'resource-icon', '<svg/>', 'emoji');
+		$picker = new TeamAppResourcePicker('Add to navigation', [$resource], []);
+		$action = new TeamAppAction('rename', 'Rename', 'action-icon', $prompt, $confirmation, $picker);
+		$entry = new TeamAppEntry('42', 'Board', 'entry-icon', '<svg/>', 'emoji', '/board/42', ['board-42'], [$action], ['path' => '/Board.whiteboard']);
+		$key = new TeamAppResourceKey('whiteboard', '42');
+		$navigation = new TeamAppNavigation([$entry], [$action], [$key]);
+		$expectedAction = [
+			'id' => 'rename', 'label' => 'Rename', 'icon' => 'action-icon',
+			'prompt' => ['title' => 'Name', 'value' => ''],
+			'confirm' => ['title' => 'Delete', 'message' => 'Delete this item?'],
+			'resourcePicker' => ['title' => 'Add to navigation', 'resources' => [[
+				'id' => '42', 'label' => 'Board', 'description' => '/Board.whiteboard',
+				'icon' => 'resource-icon', 'iconSvg' => '<svg/>', 'iconEmoji' => 'emoji',
+			]], 'selectedIds' => []],
+		];
+
+		$this->assertSame([$entry], $navigation->entries);
+		$this->assertSame([$action], $entry->actions);
+		$this->assertSame($picker, $action->resourcePicker);
+		$this->assertSame(['entries' => [[
+			'id' => '42', 'label' => 'Board', 'icon' => 'entry-icon', 'iconSvg' => '<svg/>', 'iconEmoji' => 'emoji',
+			'href' => '/board/42', 'legacyIds' => ['board-42'], 'actions' => [$expectedAction],
+			'viewData' => ['path' => '/Board.whiteboard'],
+		]], 'actions' => [$expectedAction], 'resourceKeys' => [['providerId' => 'whiteboard', 'resourceId' => '42']]], $this->decode($navigation));
+	}
+
+	public function testOmitsAbsentOptionalFields(): void {
+		$this->assertSame(['entries' => []], $this->decode(new TeamAppNavigation([])));
+		$this->assertSame(['id' => '42', 'label' => 'Board'], $this->decode(new TeamAppEntry('42', 'Board')));
+		$this->assertSame(['id' => 'rename', 'label' => 'Rename'], $this->decode(new TeamAppAction('rename', 'Rename')));
+		$this->assertSame(['title' => 'Name'], $this->decode(new TeamAppActionPrompt('Name')));
+		$this->assertSame(['id' => '42', 'label' => 'Board'], $this->decode(new TeamAppResource('42', 'Board')));
+		$this->assertSame(['title' => 'Boards', 'resources' => []], $this->decode(new TeamAppResourcePicker('Boards', [])));
+		$this->assertSame([], $this->decode(new TeamAppActionResult()));
+	}
+
+	public function testPreservesExplicitEmptyLists(): void {
+		$this->assertSame(['entries' => [], 'actions' => [], 'resourceKeys' => []], $this->decode(new TeamAppNavigation([], [], [])));
+		$this->assertSame(['id' => '42', 'label' => 'Board', 'legacyIds' => [], 'actions' => [], 'viewData' => []], $this->decode(new TeamAppEntry('42', 'Board', legacyIds: [], actions: [], viewData: [])));
+		$this->assertSame(['navigationEntryIds' => []], $this->decode(new TeamAppActionResult(navigationEntryIds: [])));
+	}
+
+	public function testSerializesActionResult(): void {
+		$result = new TeamAppActionResult(['42'], '42');
+
+		$this->assertSame(['42'], $result->navigationEntryIds);
+		$this->assertSame('42', $result->open);
+		$this->assertSame(['navigationEntryIds' => ['42'], 'open' => '42'], $this->decode($result));
+		$this->assertSame(['open' => '42'], $this->decode(new TeamAppActionResult(open: '42')));
+	}
+
+	private function decode(\JsonSerializable $value): array {
+		return json_decode(json_encode($value, JSON_THROW_ON_ERROR), true, 512, JSON_THROW_ON_ERROR);
+	}
+}