> ## Documentation Index > Fetch the complete documentation index at: https://fal.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > fal has two developer products. Model APIs run hosted models through an API key. fal Serverless deploys your own Python apps and models on fal GPUs. > To call a hosted model, start with the [Quick Start](https://fal.ai/docs/documentation/quickstart.md) and the [Model APIs overview](https://fal.ai/docs/documentation/model-apis/overview.md). > To deploy your own model with fal Serverless, start with these pages: > - [Introduction to Serverless](https://fal.ai/docs/documentation/serverless/index.md): What fal Serverless is and the three ways to deploy on it. > - [Installation & Setup](https://fal.ai/docs/documentation/development/getting-started/installation.md): Install the fal CLI with `pip install fal` and authenticate. > - [Quick Start](https://fal.ai/docs/documentation/development/getting-started/quick-start.md): Build a Hello World app, test it with `fal run`, and ship it with `fal deploy`. > - [App Lifecycle](https://fal.ai/docs/documentation/development/app-lifecycle.md): How a `fal.App` goes from code to running runners. > - [Define Your Endpoints](https://fal.ai/docs/documentation/development/endpoints-overview.md): Structure the API endpoints that your app exposes. > - [Deploy to Production](https://fal.ai/docs/documentation/deployment/deploy-to-production.md): Persistent URLs, authentication modes, and automatic scaling. > - [Machine Types](https://fal.ai/docs/documentation/deployment/machine-types.md): Available GPU and CPU machine types and how to choose one. > - [Pricing](https://fal.ai/docs/documentation/serverless/pricing.md): Per-second billing and the runner states that are billed. > - [Scaling Parameter Reference](https://fal.ai/docs/documentation/deployment/scale-your-application.md): Parameters that control runners, concurrency, and scale to zero. > - [Optimizing Cold Starts](https://fal.ai/docs/documentation/serverless/optimizations/optimize-cold-starts.md): Causes of cold starts and ways to make them shorter. > - [Examples](https://fal.ai/docs/examples/index.md): Complete Serverless apps for image, video, audio, 3D, realtime, and multi-GPU workloads. > - [Migrating to fal](https://fal.ai/docs/documentation/development/migrating-to-fal.md): Guides to move an existing Docker server or an app from another platform to fal. > fal Serverless deploys need access that the fal team approves for each account. Request access at https://fal.ai/dashboard/serverless-get-started. # Cancel a request > Cancel a queue request. If the request is in the queue, fal removes it. If the request is in progress, fal sends a cancellation signal to the runner. The model app decides how to stop the work. See [Handle cancellations](/documentation/development/handle-cancellations). ## OpenAPI ````yaml /api-reference/inference-api/openapi/queue.json put /{owner}/{app}/requests/{request_id}/cancel openapi: 3.1.0 info: title: Queue API version: v1 description: >- Submit a model request to the fal queue, then read its status and result. The queue retries requests that fail because of a temporary runner error. servers: - url: https://queue.fal.run description: Queue API. The backup host is https://queue.falrun.com. security: - apiKey: [] tags: - name: Queue paths: /{owner}/{app}/requests/{request_id}/cancel: put: tags: - Queue summary: Cancel a request description: >- Cancel a queue request. If the request is in the queue, fal removes it. If the request is in progress, fal sends a cancellation signal to the runner. The model app decides how to stop the work. See [Handle cancellations](/documentation/development/handle-cancellations). operationId: cancelQueueRequest parameters: - $ref: '#/components/parameters/StatusOwner' - $ref: '#/components/parameters/StatusApp' - $ref: '#/components/parameters/RequestId' responses: '200': description: fal removed the request from the queue. content: application/json: schema: $ref: '#/components/schemas/CancelResponse' example: status: OK '202': description: >- The request is in progress. fal sent a cancellation signal to the runner. content: application/json: schema: $ref: '#/components/schemas/CancelResponse' example: status: CANCELLATION_REQUESTED '400': description: The request is already complete. content: application/json: schema: $ref: '#/components/schemas/CancelResponse' example: status: ALREADY_COMPLETED '401': $ref: '#/components/responses/BadCredentials' '404': description: >- The request does not exist, or it belongs to a different account. The API returns the same response in both cases. content: application/json: schema: $ref: '#/components/schemas/NotFoundStatus' '500': $ref: '#/components/responses/InternalError' components: parameters: StatusOwner: name: owner in: path required: true description: >- The owner of the model, for example `blackforestlabs`. Use the same value as in the submit request. schema: type: string example: blackforestlabs StatusApp: name: app in: path required: true description: >- The model app name, for example `flux-3-max`. Do not add the endpoint path. The `status_url`, `response_url`, and `cancel_url` fields contain the correct URL. schema: type: string example: flux-3-max RequestId: name: request_id in: path required: true description: The request ID that the submit response returned. schema: type: string format: uuid schemas: CancelResponse: type: object properties: status: type: string enum: - OK - CANCELLATION_REQUESTED - ALREADY_COMPLETED - NOT_FOUND required: - status NotFoundStatus: type: object properties: status: type: string enum: - NOT_FOUND required: - status DetailError: type: object description: A general error. properties: detail: type: string type: type: string description: >- A machine-readable reason, for some errors. Examples are `rejected_key`, `permission_denied`, and `resource_restricted`. required: - detail responses: BadCredentials: description: The credentials are not valid, or the app requires authentication. content: application/json: schema: $ref: '#/components/schemas/DetailError' InternalError: description: An internal error occurred. Retry the request. content: application/json: schema: $ref: '#/components/schemas/DetailError' securitySchemes: apiKey: type: apiKey in: header name: Authorization description: >- Send your fal API key in the `Authorization` header with the `Key` prefix, for example `Authorization: Key $FAL_KEY`. Public models also accept requests without a key. See [Authentication](/documentation/model-apis/authentication/key-based). ````