> ## Documentation Index > Fetch the complete documentation index at: https://docs.comfy.org/llms.txt > Use this file to discover all available pages before exploring further. # Request cancellation > Requests cancellation and returns the current job object — `canceling` (interruption takes effect at node/step boundaries), `canceled` where the provider's record already shows the interrupt, or already-terminal. Idempotent: canceling a finished job is a no-op returning the terminal state. On serverless, GPU seconds consumed before the interrupt takes effect are still billed. ## OpenAPI ````yaml /openapi-v2.yaml post /api/v2/jobs/{id}/cancel openapi: 3.0.3 info: title: Comfy API v2 version: 2.0.0 description: | The official, versioned HTTP API for running ComfyUI workflows from external applications: upload inputs, submit a workflow, observe execution, retrieve results. Design principles: - **Poll-first.** Every capability is reachable via plain GET polling; the SSE stream is a live enhancement, never the source of truth. - **Everything is resumable.** Submission is idempotent; job state and outputs are retrievable by ID until `expires_at`. - **UUID identity, content-addressed dedup.** Assets are UUID-identified records over blobs keyed by a server-computed blake3 hash. The hash is nullable and may be computed lazily. - **Follow links, don't build URLs.** Responses embed follow-up URLs. Additive changes only within v2; breaking changes require v3. servers: - url: http://127.0.0.1:8189 description: Self-hosted (comfy-api-proxy) - url: https://cloud.comfy.org description: Comfy Cloud - url: https://{deployment}.run.comfy.app description: Serverless deployment variables: deployment: description: >- DNS-safe deployment id (subdomain label). Staging uses {deployment}.stg.run.comfy.app. default: dep-1234abcd-56ef-7890-abcd-ef1234567890 security: - bearerAuth: [] - {} tags: - name: assets description: UUID-identified records over content-addressed blobs. - name: jobs description: One execution of a workflow — durable, pollable, cancelable. paths: /api/v2/jobs/{id}/cancel: post: tags: - jobs summary: Request cancellation description: | Requests cancellation and returns the current job object — `canceling` (interruption takes effect at node/step boundaries), `canceled` where the provider's record already shows the interrupt, or already-terminal. Idempotent: canceling a finished job is a no-op returning the terminal state. On serverless, GPU seconds consumed before the interrupt takes effect are still billed. operationId: cancelJob parameters: - $ref: '#/components/parameters/JobId' responses: '200': description: Current job state. content: application/json: schema: $ref: '#/components/schemas/Job' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/UpstreamError' components: parameters: JobId: name: id in: path required: true schema: type: string example: 7f3d2c1b-9a8e-4d6f-b012-3c4d5e6f7a8b schemas: Job: type: object description: >- One execution of a workflow. Durable from creation until `expires_at`; `outputs` populates incrementally during execution. required: - id - status - created_at - started_at - completed_at - expires_at - queue_position - progress - outputs - error - urls properties: id: type: string example: 7f3d2c1b-9a8e-4d6f-b012-3c4d5e6f7a8b status: $ref: '#/components/schemas/JobStatus' created_at: type: string format: date-time started_at: type: string format: date-time nullable: true completed_at: type: string format: date-time nullable: true expires_at: type: string format: date-time description: Retention deadline — a platform property, not an API constant. queue_position: type: integer nullable: true progress: allOf: - $ref: '#/components/schemas/Progress' nullable: true description: The latest progress snapshot; same data the SSE stream pushes. outputs: type: array items: $ref: '#/components/schemas/Output' error: allOf: - $ref: '#/components/schemas/JobError' nullable: true metrics: type: object description: >- Values are nullable (a metric not yet available — e.g. `execution_ms` before a job starts running — is `null`, not omitted); the example below is deliberately all-non-null purely to work around a Spectral/nimma lint-tooling crash on a literal `null` inside a schema `example` combined with `additionalProperties.nullable: true` — the schema itself is unchanged and still allows null values at runtime. additionalProperties: type: integer nullable: true example: queue_ms: 9000 execution_ms: 42000 urls: $ref: '#/components/schemas/JobUrls' deployment_id: type: string description: >- The deployment the job was sent to: the id in the address it was posted at, which stays the same when the deployment moves to another release. Absent on a surface that runs jobs on no deployment. example: dep-0f19a2b3c4d5 release_id: type: string description: >- The release of the deployment's build that ran the job, which can differ from the release the deployment runs now. Absent where the serving surface does not report it. example: 7c1e9a40-3b2d-4f6a-9e81-0c5d2a7b4f13 JobStatus: type: string enum: - queued - running - succeeded - canceling - canceled - failed - expired description: | Lifecycle: queued → running → succeeded | failed | expired; a cancel request, or the deletion of the deployment the job is running on, moves running → canceling → canceled. Terminal states: succeeded, canceled, failed, expired. Progress: type: object description: >- Server-computed progress snapshot (node-count and sampler-step weighted). Complete per snapshot — one fully re-syncs a client. required: - value - nodes_done - nodes_total properties: value: type: number format: double minimum: 0 maximum: 1 description: Overall fraction, server-computed. example: 0.42 nodes_done: type: integer example: 11 nodes_total: type: integer example: 31 current_node: type: string nullable: true example: '12' current_node_class: type: string nullable: true example: KSampler step: type: integer nullable: true example: 21 steps: type: integer nullable: true example: 50 message: type: string nullable: true example: KSampler 21/50 Output: type: object description: >- A committed job output. Outputs are assets: `id` is the asset UUID, retrievable via GET /api/v2/assets/{id} for as long as the job is retained. `hash` is lazily computed and may be null on the retrieval hot path. required: - node_id - name - type - content_type - size_bytes - id - hash - url - url_expires_at properties: node_id: type: string description: >- The workflow node that reported this file; empty when the worker named none. example: '9' name: type: string example: ComfyUI_00001_.png type: $ref: '#/components/schemas/OutputType' content_type: type: string example: image/png size_bytes: type: integer format: int64 example: 1848320 id: type: string description: Asset UUID. example: 9f8a1c0d-2b3e-4f56-... hash: type: string nullable: true description: '`blake3:`; null until lazily computed.' url: type: string format: uri url_expires_at: type: string format: date-time job_id: type: string nullable: true description: ID of the job that produced this output. JobError: type: object description: Execution failure detail, carried in `job.error` (not an HTTP error). required: - code - message properties: code: type: string example: node_execution_error message: type: string description: >- Why the job failed, written for a person to read. On a serverless deployment, where ComfyUI refused the workflow, it names the rejected nodes it has room for and their reasons, which `node_errors` carries in full. Its wording may change; read `code` and `node_errors` rather than matching this text. node_id: type: string nullable: true class_type: type: string nullable: true traceback: type: string nullable: true node_errors: type: object description: >- Every node ComfyUI rejected when it refused the workflow before running any of it (a value outside its allowed range, a model the deployment does not contain, a graph that loops back on itself), keyed by node id, under the names ComfyUI gave them. Absent when the workflow ran and a node raised: `node_id`, `class_type` and `traceback` describe that failure instead. additionalProperties: $ref: '#/components/schemas/JobNodeError' example: '22': class_type: LoraLoader errors: - type: value_not_in_list message: Value not in list details: >- lora_name: 'sdxl\Hyper-SDXL-8steps-lora.safetensors' not in (list of length 40) JobUrls: type: object description: >- Embedded follow-up links — follow these, don't build URLs. A link is either an absolute URL or a host-relative reference (leading `/`) that already includes any prefix the serving surface is mounted under (e.g. a serverless gateway's `/deployment/{deployment_id}/api/v2`). Clients MUST resolve a host-relative link against the request origin (scheme + authority), never against a configured base URL — joining it to a base URL that carries the same mount prefix duplicates the prefix. required: - self - events - cancel properties: self: type: string format: uri-reference events: type: string format: uri-reference cancel: type: string format: uri-reference logs: type: string format: uri-reference description: >- Where to read what this run printed. Present on any surface that captures execution logs, which is why it is the one link here that is optional: absent means this surface captures none, for any job, so a client can stop looking without spending a request on an answer it already has. Follow this link rather than building the path from the job id. The two are not interchangeable: a surface may be mounted under a prefix this link already carries and a hand-built path would not, and a surface that does not implement the operation at all answers a routing `404` — indistinguishable, to the client, from the `404` that means the job itself is gone. Present does NOT mean this job has a log, and it is deliberately not a signal about one: a surface that captures logs offers the link on every job, including those it will answer `204` for and those whose log it withholds. Read the log, not the link. ErrorEnvelope: type: object description: > Shared error envelope with machine-readable codes. Core codes (v1): `invalid_workflow` (422), `workflow_format_ui` (422), `missing_asset` (422), `hash_mismatch` (409), `blob_not_found` (404), `idempotency_key_reuse` (422), `queue_full` (429 + Retry-After), `rate_limited` (429 + Retry-After: the caller is past a request rate limit; retry), `insufficient_credits` (402), `not_found` (404), `unauthorized` (401), `forbidden` (403). Deployment-scoped surfaces add: `deployment_not_ready` (429 + Retry-After — the deployment can still reach ready; retry), `deployment_unavailable` (429 + Retry-After: the deployment is ready but its GPU provider is not taking work on it yet; retry), `deployment_stopped` (422 — terminal deployment state; a retry cannot succeed without operator action), `invalid_request` (422: a malformed asset upload or asset-from-hash field), `content_blocked` (451: content moderation flagged the asset's bytes) and `sso_required` (403: the key is valid, but the account must sign in through its organization's single sign-on, which does not accept this key). A 429 is disambiguated by `error.code` alone; clients should treat any 429 + Retry-After as "back off and retry". required: - error properties: error: type: object required: - code - message properties: code: type: string example: invalid_workflow message: type: string example: 'Node 12 (KSampler): required input ''model'' is not connected' details: type: object nullable: true additionalProperties: true description: >- Machine-readable detail for the code. When it carries `node_errors`, that is keyed by node id and each value is a `JobNodeError`, the same shape as a job's `error.node_errors`, whether the refusal came at submit (for example `unknown_node_class`, a node class the deployment's build does not contain) or from ComfyUI after dispatch. example: node_errors: '12': class_type: SomeCustomNode errors: - type: unknown_node_class message: >- this deployment's build does not contain the node class SomeCustomNode. unknown_node_classes: - SomeCustomNode OutputType: type: string enum: - image - video - audio - text - file - latent description: Normalized output kind — nothing silently dropped. JobNodeError: type: object description: >- One node that was rejected, and why: by ComfyUI when it refused the workflow after dispatch, or by the gateway when it refused the workflow at submit. required: - errors properties: class_type: type: string errors: type: array items: $ref: '#/components/schemas/JobNodeErrorReason' JobNodeErrorReason: type: object description: >- One problem found with a node. `type` is the code for it: ComfyUI's (for example `value_not_in_list`, `value_bigger_than_max`, `dependency_cycle`), or the gateway's `unknown_node_class` (a node class the deployment's build does not contain). ComfyUI's `missing_node_type` means the same as `unknown_node_class`, found after dispatch rather than at submit. For either, `message` ends naming the node pack that provides the class where the Comfy node registry knows one. `details` usually starts with the input it is about. required: - type - message properties: type: type: string example: value_not_in_list message: type: string example: Value not in list details: type: string responses: Unauthorized: description: '`unauthorized` — missing or invalid credentials.' content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' Forbidden: description: >- `forbidden` — authenticated but not allowed. On a serverless deployment, also `sso_required` — the key is valid, but the account must sign in through its organization's single sign-on, which does not accept this key; it can come back on any operation. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' NotFound: description: '`not_found`.' content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' RateLimited: description: >- `rate_limited` — the caller has exceeded a request rate limit for this account. Account/rate-scoped, not resource-specific — this can be returned even for a job, asset or deployment the caller doesn't own or that doesn't exist. headers: Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' UpstreamError: description: >- `upstream_error` — an unexpected failure reaching or processing the request in this implementation's backing services. The message is always a generic, safe-to-display string; implementation detail (the specific upstream, its error text, transport failures) is never included here — see each implementation's own error-mapping notes. Every operation in this contract can fail this way. content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' headers: RetryAfter: schema: type: integer description: Seconds to wait before retrying. securitySchemes: bearerAuth: type: http scheme: bearer description: >- `Authorization: Bearer `. The credential is one of: an account-scoped API key (`comfyui-…`), accepted on Cloud and serverless; a Comfy Cloud session JWT; or an OAuth access token issued for the Comfy Cloud resource. Which kinds a given deployment accepts is deployment configuration — an API key always works on Cloud and serverless, and a deployment that does not accept JWT bearers answers `401` with a message saying so. Self-hosted accepts unauthenticated requests by default and can be configured with a static bearer token. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.