> ## Documentation Index > Fetch the complete documentation index at: https://checkfu.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Create a webhook endpoint > Subscribe an application to platform event types over a public HTTPS url. Omit `event_types` entirely to subscribe to the whole catalog; `null` is rejected at creation and an empty array is rejected everywhere. Requires a non-empty Idempotency-Key, and this response is the one place the `whsec_` signing secret appears — an exact keyed replay returns it again while that endpoint generation stays live. Checkfu support posture: alpha; hosted. Required evidence journey: webhook-delivery. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. ## OpenAPI ````yaml /openapi.json post /v1/webhook-endpoints openapi: 3.1.0 info: title: Checkfu API version: '2026-08-29' description: >- Authentication is declared per operation: API-key, runtime, or connector bearer; Automation signature; or credential-free pairing redemption. Every general Checkfu REST request requires the dated `Checkfu-Version` header (one of: 2026-08-29); the three MCP JSON-RPC transports use `MCP-Protocol-Version`, A2A uses `A2A-Version`, and the provider OAuth callback carries neither Checkfu header. API keys resolve one Workspace without a request selector; authenticated responses identify it with `Checkfu-Workspace-Id`. servers: - url: https://api.checkfu.com security: - bearerAuth: [] tags: - name: organizations - name: sourceRepositories - name: tenants - name: workspaces - name: principals - name: principalGroups - name: principalAccessCredentials - name: apiKeys - name: agents - name: harnesses - name: harnessRuntime - name: computerProfiles - name: permissionAssignments - name: actionPolicies - name: files - name: memoryStores - name: dreams - name: modelCredentials - name: modelRoutingProfiles - name: blueprintInstallations - name: toolSources - name: skills - name: skillSources - name: agentSources - name: skillProposals - name: instructionProposals - name: catalog - name: concepts - name: support - name: connections - name: connectionVaults - name: connectionAssignments - name: connectedRuntimes - name: projects - name: collaboration - name: automationGraphs - name: automations - name: actionApprovals - name: standingApprovals - name: usage - name: models - name: outcomes - name: budgets - name: billing - name: sessions - name: audit - name: sessionExports - name: runs - name: runnerPools - name: transcripts - name: sessionWatches - name: sessionHandoffs - name: sessionCapsules - name: sessionTrajectories - name: webhookEndpoints - name: integrationGateway - name: agentDeployments - name: workEnvironments - name: computers - name: computerScreens - name: computerBrowserObservations - name: computerBrowserActions - name: environments - name: vaults - name: apiMcp - name: a2a paths: /v1/webhook-endpoints: post: tags: - webhookEndpoints summary: Create a webhook endpoint description: >- Subscribe an application to platform event types over a public HTTPS url. Omit `event_types` entirely to subscribe to the whole catalog; `null` is rejected at creation and an empty array is rejected everywhere. Requires a non-empty Idempotency-Key, and this response is the one place the `whsec_` signing secret appears — an exact keyed replay returns it again while that endpoint generation stays live. Checkfu support posture: alpha; hosted. Required evidence journey: webhook-delivery. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. operationId: webhookEndpoints.createWebhookEndpoint parameters: - name: checkfu-version in: header schema: type: string enum: - '2026-08-29' required: true - name: idempotency-key in: header schema: type: string allOf: - maxLength: 255 - minLength: 1 required: true requestBody: content: application/json: schema: type: object properties: url: $ref: '#/components/schemas/PublicHttpsUrl' event_types: type: array prefixItems: - $ref: '#/components/schemas/Union_407' minItems: 1 items: $ref: '#/components/schemas/Union_407' required: - url additionalProperties: false required: true responses: '201': description: Success content: application/json: schema: type: object properties: webhook_endpoint: $ref: '#/components/schemas/Objects_447' secret: type: string allOf: - pattern: ^whsec_[A-Za-z0-9_-]{43}$ required: - webhook_endpoint - secret additionalProperties: false headers: checkfu-workspace-id: description: The Workspace resolved from the authenticated bearer credential. required: true schema: $ref: '#/components/schemas/WorkspaceId' '400': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object properties: type: type: string enum: - validation.malformed message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#validation-malformed description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false '401': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object required: - type - message - more properties: type: type: string enum: - auth.invalid_key message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#auth-invalid-key description: >- Stable public documentation and remedy for this error type. additionalProperties: false additionalProperties: false '403': description: >- The organization, tenant, or workspace backing this key is administratively disabled. | Deployment governance or retention policy denied the request. content: application/json: schema: anyOf: - type: object required: - error properties: error: type: object properties: type: type: string enum: - auth.disabled_tenancy message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#auth-disabled-tenancy description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false - $ref: '#/components/schemas/PolicyDeniedError' '404': description: >- The requested resource does not exist in the resolved deployment boundary. content: application/json: schema: $ref: '#/components/schemas/ValidationNotFoundError' '409': description: >- The request conflicts with the resource's current state. | An idempotent mutation conflicts with a completed or in-progress request for the same key. content: application/json: schema: anyOf: - $ref: '#/components/schemas/ValidationConflictError' - $ref: '#/components/schemas/IdempotencyConflictError' '429': description: Typed Checkfu wire error headers: retry-after: description: >- Delay in seconds for rate limits or deployment quotas with a known release or UTC reset boundary required: false schema: type: integer minimum: 1 content: application/json: schema: type: object required: - error properties: error: type: object required: - type - message - more properties: type: type: string enum: - budget.exceeded message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#budget-exceeded description: >- Stable public documentation and remedy for this error type. additionalProperties: false additionalProperties: false '500': description: >- An unexpected internal failure occurred; the message contains an opaque incident reference. content: application/json: schema: $ref: '#/components/schemas/RuntimeInternalError' security: - bearerAuth: [] components: schemas: PublicHttpsUrl: type: string allOf: - pattern: ^https:\/\/[^\s]+$ - maxLength: 2048 Union_407: type: string enum: - session.status_pending - session.status_provisioning - session.status_running - session.status_reconciling - session.status_waiting - session.status_idle - session.status_paused - session.status_completed - session.status_failed - session.status_canceled - run.created - run.started - run.start_timed_out - run.attempt_requeued - run.requires_action - run.action_authorized - run.resumed - run.completed - run.failed - run.canceled - session.budget_reached - action_approval.pending - action_approval.resolved - outcome.evaluation_started - outcome.evaluation_completed - session.thread_created - session.thread_idled - session.thread_terminated - memory_store.created - memory_store.archived - memory_store.deleted - agent.created - agent.updated - agent.archived - connection.created - connection.revoked - connection.refresh_failed - vault_credential.refresh_failed - automation.created - automation.paused - automation.resumed - automation.deleted - workspace.created - workspace.updated - sandbox_profile.created - sandbox_profile.updated Objects_447: type: object properties: id: $ref: '#/components/schemas/WebhookEndpointId' workspace_id: $ref: '#/components/schemas/WorkspaceId' url: $ref: '#/components/schemas/PublicHttpsUrl' event_types: anyOf: - type: array prefixItems: - $ref: '#/components/schemas/Union_407' minItems: 1 items: $ref: '#/components/schemas/Union_407' - type: 'null' status: type: string enum: - active - disabled disabled_reason: anyOf: - type: string enum: - delivery_failures - type: 'null' consecutive_failures: type: integer allOf: - minimum: 0 last_success_at: anyOf: - type: string - type: 'null' last_failure_at: anyOf: - type: string - type: 'null' version: type: integer allOf: - exclusiveMinimum: 0 created_at: type: string updated_at: type: string required: - id - workspace_id - url - event_types - status - disabled_reason - consecutive_failures - last_success_at - last_failure_at - version - created_at - updated_at additionalProperties: false WorkspaceId: type: string allOf: - pattern: ^wrkspc_[0-9a-f]{32}$ PolicyDeniedError: type: object properties: error: type: object properties: type: type: string enum: - policy.denied message: type: string more: type: string enum: - https://docs.checkfu.com/reference/errors#policy-denied description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: Deployment governance or retention policy denied the request. ValidationNotFoundError: type: object properties: error: type: object properties: type: type: string enum: - validation.not_found message: type: string more: type: string enum: - https://docs.checkfu.com/reference/errors#validation-not-found description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: >- The requested resource does not exist in the resolved deployment boundary. ValidationConflictError: type: object properties: error: type: object properties: type: type: string enum: - validation.conflict message: type: string more: type: string enum: - https://docs.checkfu.com/reference/errors#validation-conflict description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: The request conflicts with the resource's current state. IdempotencyConflictError: anyOf: - $ref: '#/components/schemas/ValidationIdempotencyConflictError' - $ref: '#/components/schemas/ValidationIdempotencyInProgressError' description: >- An idempotent mutation conflicts with a completed or in-progress request for the same key. RuntimeInternalError: type: object properties: error: type: object properties: type: type: string enum: - runtime.internal message: type: string more: type: string enum: - https://docs.checkfu.com/reference/errors#runtime-internal description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: >- An unexpected internal failure occurred; the message contains an opaque incident reference. WebhookEndpointId: type: string allOf: - pattern: ^whe_[0-9a-f]{32}$ ValidationIdempotencyConflictError: type: object properties: error: type: object properties: type: type: string enum: - validation.idempotency_conflict message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#validation-idempotency-conflict description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: The Idempotency-Key is already bound to a different request. ValidationIdempotencyInProgressError: type: object properties: error: type: object properties: type: type: string enum: - validation.idempotency_in_progress message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#validation-idempotency-in-progress description: Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false required: - error additionalProperties: false description: >- An identical idempotent request is still in progress and may be retried later. securitySchemes: bearerAuth: type: http scheme: bearer ````