> ## Documentation Index
> Fetch the complete documentation index at: https://arize-ax.mintlify.site/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a webhook subscription

> Subscribe a webhook to one event on a prompt or evaluator. To deliver
several events to the same webhook, create one subscription per event.

**Payload Requirements**
- `webhook_id`, `source_type`, `source_id`, and `event` are required.
- `webhook_id` must be a webhook in the source's organization; unknown
  webhooks yield a 404.
- `event` must belong to the source type: prompt events for `PROMPT`
  sources and evaluator events for `EVALUATOR` sources.
  Other combinations are rejected with a 422.
- A webhook can subscribe to a given event on a given source only once
  (409 on conflict).
- At most 200 webhooks may subscribe to the same event on a source;
  requests that would exceed this limit are rejected with a 422.

Creating a subscription requires `PROMPT_UPDATE` for a prompt source or
`EVALUATOR_UPDATE` for an evaluator source. Callers with the matching
`PROMPT_READ` or `EVALUATOR_READ` permission but not the required update
permission receive a 403; sources the caller cannot read yield a 404.

<Warning>This endpoint is in alpha, read more [here](https://arize.com/docs/ax/rest-reference#api-version-stages).</Warning>




## OpenAPI

````yaml https://api.arize.com/v2/spec.yaml post /v2/webhook-subscriptions
openapi: 3.0.3
info:
  title: Arize REST API
  version: 2.0.0
  description: |
    API specification for the backend data server. The API is hosted globally
    at https://api.arize.com/v2 or in your own environment.
  license:
    name: Apache-2.0
    url: https://www.apache.org/licenses/LICENSE-2.0
servers:
  - description: Global
    url: https://api.arize.com
  - description: Regional
    url: https://api.{region}.arize.com
    variables:
      region:
        default: eu-west-1a
        enum:
          - eu-west-1a
          - ca-central-1a
  - description: Custom Host
    url: https://{host}
    variables:
      host:
        default: api.arize.com
security:
  - bearerAuth: []
tags:
  - name: AI Integrations
    description: |
      AI integrations configure access to external LLM providers (e.g. OpenAI,
      Azure OpenAI, AWS Bedrock, Vertex AI). Integrations can be scoped to the
      entire account, a specific organization, or a specific space.
  - name: Annotation Configs
    description: >
      Annotation configs allow you to define consistent annotation schemas that

      can be reused across your workspace, ensuring evaluations are structured
      and

      comparable over time.
  - name: Annotation Queues
    description: >
      Annotation queues help you organize and manage human evaluation workflows.

      Use queues to assign spans or examples to annotators for review and
      labeling.
  - name: API Keys
    description: >
      API keys are used to authenticate requests to the Arize API. List your
      keys

      to view metadata; the raw secret is never returned after creation.
  - name: Audit Logs
    description: >
      Audit logs record authenticated user actions within an account, providing
      a

      chronological trail for security and compliance review. Access requires

      account admin privileges and audit logging to be enabled.
  - name: Datasets
    description: |
      Datasets are structured, version-controlled example collections you use to
      run, evaluate, and track LLM experiments.
  - name: Evaluators
    description: >
      Evaluators are reusable evaluation configurations used to assess the
      quality

      of LLM outputs. They can be template-based (using LLM judges) or
      code-based.
  - name: Experiments
    description: >
      Experiments let you systematically test prompt/model changes using
      datasets,

      tasks, and evaluators.
  - name: Integrations
    description: >
      Integrations configure access to external LLM providers (e.g. OpenAI,

      Azure OpenAI, AWS Bedrock, Vertex AI), notifications services (e.g.
      PagerDuty, Slack), and

      your own agents. Integrations can be scoped to the entire account, a
      specific

      organization, or a specific space.
  - name: Monitors
    description: >
      Monitors continuously track a metric over your model or LLM application
      data

      and alert you when it crosses a threshold. Each monitor watches a single

      metric - data quality, model performance, drift, a custom metric, or a

      tracing metric - and moves between statuses as the metric passes in and
      out of its 

      healthy range.
  - name: Organizations
    description: >
      Organizations are top-level containers within an Arize AX account for
      grouping spaces.
  - name: Projects
    description: |
      Projects represent LLM applications being monitored in Arize where you can
      observe traces and spans.
  - name: Prompts
    description: >
      Prompts are reusable, versioned templates for LLM interactions. Use
      prompts

      to standardize and manage how you interact with LLMs across your
      application.
  - name: Resource Restrictions
    description: |
      Endpoints for restricting and unrestricting resources (projects, models).
  - name: Role Bindings
    description: |
      Role bindings assign a role to a user on a resource. REST currently
      supports space- and project-scoped bindings.
  - name: Roles
    description: >
      Roles define sets of permissions that can be assigned to users within an

      account. Create custom roles to tailor access control to your team's
      needs.
  - name: Spaces
    description: >
      Spaces are containers within an organization for grouping related
      projects,

      datasets, and experiments, enabling collaboration or isolated
      experimentation

      with role-based access control.
  - name: Spans
    description: |
      Spans represent individual operations within a trace. A span captures the
      timing, status, and attributes of a single operation in your application.
  - name: Tags
    description: |
      Tags are reusable labels defined once per space and attached to resources
      across the platform, so the same vocabulary can be applied to projects,
      datasets, prompts, and more. Tags are shared: renaming or deleting a tag
      affects every resource it is attached to.
  - name: Tasks
    description: |
      Tasks are configurable units of work that tie one or more evaluators to a
      data source (project or dataset). Use tasks to automate evaluation of LLM
      outputs, with support for continuous evaluation and backfill runs.
  - name: Traces
    description: |
      A trace is the collection of spans sharing a trace ID, representing a
      single end-to-end request through an LLM application. Use the Traces
      endpoint to retrieve traces with all of their spans in one call.
  - name: Users
    description: >
      Users represent members of an account. The Users endpoints allow creating,

      listing, updating (display name), and removing users from the account
      programmatically.
  - name: Webhooks
    description: >
      Webhooks are organization-owned destinations that receive event deliveries

      over HTTPS. Deliveries are authenticated with a bearer token or signed
      with

      an HMAC signing secret — the secret is returned exactly once, when the

      webhook is created. Delivery attempts are recorded and can be listed for

      debugging. To choose which events a webhook receives, manage its

      subscriptions through the prompt and evaluator webhook-subscription

      endpoints.
paths:
  /v2/webhook-subscriptions:
    post:
      tags:
        - Webhooks
      summary: Create a webhook subscription
      description: >
        Subscribe a webhook to one event on a prompt or evaluator. To deliver

        several events to the same webhook, create one subscription per event.


        **Payload Requirements**

        - `webhook_id`, `source_type`, `source_id`, and `event` are required.

        - `webhook_id` must be a webhook in the source's organization; unknown
          webhooks yield a 404.
        - `event` must belong to the source type: prompt events for `PROMPT`
          sources and evaluator events for `EVALUATOR` sources.
          Other combinations are rejected with a 422.
        - A webhook can subscribe to a given event on a given source only once
          (409 on conflict).
        - At most 200 webhooks may subscribe to the same event on a source;
          requests that would exceed this limit are rejected with a 422.

        Creating a subscription requires `PROMPT_UPDATE` for a prompt source or

        `EVALUATOR_UPDATE` for an evaluator source. Callers with the matching

        `PROMPT_READ` or `EVALUATOR_READ` permission but not the required update

        permission receive a 403; sources the caller cannot read yield a 404.


        <Warning>This endpoint is in alpha, read more
        [here](https://arize.com/docs/ax/rest-reference#api-version-stages).</Warning>
      operationId: create_webhook_subscription
      requestBody:
        $ref: '#/components/requestBodies/CreateWebhookSubscriptionRequestBody'
      responses:
        '201':
          $ref: '#/components/responses/CreateWebhookSubscriptionResponse'
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
        '404':
          $ref: '#/components/responses/NotFound'
        '409':
          $ref: '#/components/responses/Conflict'
        '422':
          $ref: '#/components/responses/UnprocessableEntity'
        '429':
          $ref: '#/components/responses/RateLimitExceeded'
components:
  requestBodies:
    CreateWebhookSubscriptionRequestBody:
      description: >-
        Body containing the webhook, the source to attach it to, and the event
        to deliver
      required: true
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/CreateWebhookSubscriptionRequest'
          examples:
            prompt_labeled:
              summary: Notify a webhook when a prompt version is labeled
              value:
                webhook_id: V2ViaG9vazoxMjM0NQ==
                source_type: PROMPT
                source_id: UHJvbXB0OjEyMzQ1
                event: PROMPT_VERSION_LABELED
            evaluator_version_created:
              summary: Notify a webhook when an evaluator version is created
              value:
                webhook_id: V2ViaG9vazoxMjM0Ng==
                source_type: EVALUATOR
                source_id: RXZhbHVhdG9yOjEyMzQ1
                event: EVALUATOR_VERSION_CREATED
  responses:
    CreateWebhookSubscriptionResponse:
      description: The created webhook subscription
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/WebhookSubscription'
          example:
            id: V2ViaG9va1N1YnNjcmlwdGlvbjoxMjM0NQ==
            webhook_id: V2ViaG9vazoxMjM0NQ==
            source_type: PROMPT
            source_id: UHJvbXB0OjEyMzQ1
            event: PROMPT_VERSION_LABELED
            created_at: '2026-08-01T12:00:00Z'
    BadRequest:
      description: Invalid request
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 400
            title: Invalid request parameters
            detail: The 'name' field is required and must be a non-empty string.
            instance: /resource
            type: https://arize.com/docs/ax/rest-reference/errors#invalid-request
    Unauthorized:
      description: Authentication is required
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 401
            title: Authentication required
            detail: You must be authenticated to access this resource.
            instance: /resource
            type: >-
              https://arize.com/docs/ax/rest-reference/errors#authentication-required
    Forbidden:
      description: Insufficient permissions to access this resource
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 403
            title: Access forbidden
            detail: You do not have permission to access this resource.
            instance: /resource/12345
            type: https://arize.com/docs/ax/rest-reference/errors#access-forbidden
    NotFound:
      description: Not found
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 404
            title: Resource not found
            detail: The requested resource with ID '12345' was not found.
            instance: /resource/12345
            type: https://arize.com/docs/ax/rest-reference/errors#resource-not-found
    Conflict:
      description: Resource conflict
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 409
            title: Resource conflict
            detail: A resource with the given identifier already exists.
            instance: /resource
            type: https://arize.com/docs/ax/rest-reference/errors#resource-conflict
    UnprocessableEntity:
      description: Unprocessable entity
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 422
            title: Unprocessable Entity
            detail: One or more fields failed validation.
            instance: /resource/12345
            type: >-
              https://arize.com/docs/ax/rest-reference/errors#unprocessable-entity
    RateLimitExceeded:
      description: Rate limit exceeded
      headers:
        Retry-After:
          description: |
            When throttled (429), how long to wait before retrying. Value is
            either a delta-seconds integer.
          schema:
            type: integer
            minimum: 0
          example: 42
      content:
        application/problem+json:
          schema:
            $ref: '#/components/schemas/Problem'
          example:
            status: 429
            title: Rate limit exceeded
            detail: >-
              You have exceeded the allowed number of requests. Please try again
              later.
            instance: /resource
            type: >-
              https://arize.com/docs/ax/rest-reference/errors#rate-limit-exceeded
  schemas:
    CreateWebhookSubscriptionRequest:
      type: object
      required:
        - webhook_id
        - source_type
        - source_id
        - event
      properties:
        webhook_id:
          allOf:
            - $ref: '#/components/schemas/Id'
          description: >-
            The unique identifier of the webhook to deliver the event to. Must
            belong to the source's organization.
        source_type:
          allOf:
            - $ref: '#/components/schemas/WebhookSourceType'
          description: The kind of resource to attach the webhook to
        source_id:
          allOf:
            - $ref: '#/components/schemas/Id'
          description: >-
            The unique identifier of the prompt or evaluator to attach the
            webhook to
        event:
          allOf:
            - $ref: '#/components/schemas/WebhookEventType'
          description: The event to deliver. Must belong to the source type.
      additionalProperties: false
    WebhookSubscription:
      type: object
      required:
        - id
        - webhook_id
        - source_type
        - source_id
        - event
        - created_at
      properties:
        id:
          allOf:
            - $ref: '#/components/schemas/Id'
          description: Unique identifier for the subscription
        webhook_id:
          allOf:
            - $ref: '#/components/schemas/Id'
          description: The unique identifier of the webhook that receives the event
        source_type:
          allOf:
            - $ref: '#/components/schemas/WebhookSourceType'
          description: The kind of resource the subscription is attached to
        source_id:
          allOf:
            - $ref: '#/components/schemas/Id'
          description: >-
            The unique identifier of the prompt or evaluator the subscription is
            attached to
        event:
          allOf:
            - $ref: '#/components/schemas/WebhookEventType'
          description: The event delivered to the webhook
        created_at:
          type: string
          format: date-time
          description: Timestamp for when the subscription was created
      description: |
        A subscription delivers one event from one prompt or evaluator to one
        webhook. A webhook that should receive several events from the same
        resource has one subscription per event.
      additionalProperties: false
      x-forward-compatible: true
    Problem:
      type: object
      description: RFC 9457 Problem Details
      properties:
        title:
          type: string
          description: A short, human-readable summary of the problem type
        status:
          type: integer
          description: >-
            The HTTP status code generated by the origin server for this
            occurrence of the problem
        type:
          type: string
          format: uri-reference
          description: A URI reference that identifies the problem type
        detail:
          type: string
          description: >-
            A human-readable explanation specific to this occurrence of the
            problem
        instance:
          type: string
          format: uri-reference
          description: >-
            A URI reference that identifies the specific occurrence of the
            problem
      required:
        - title
        - status
      additionalProperties: false
      x-forward-compatible: true
    Id:
      type: string
      description: A universally unique identifier (base64-encoded opaque string).
      example: RW50aXR5OjEyMzQ1
    WebhookSourceType:
      type: string
      enum:
        - PROMPT
        - EVALUATOR
      description: |
        The kind of resource a webhook subscription is attached to.
        - `PROMPT` — `source_id` is a prompt id. Prompt events apply.
        - `EVALUATOR` — `source_id` is an evaluator id. Evaluator events apply.
    WebhookEventType:
      type: string
      enum:
        - PROMPT_VERSION_CREATED
        - PROMPT_VERSION_LABELED
        - PROMPT_VERSION_UNLABELED
        - EVALUATOR_VERSION_CREATED
      description: >
        An event that a webhook can subscribe to.

        - `PROMPT_VERSION_CREATED` — a new version of the prompt was created.

        - `PROMPT_VERSION_LABELED` — a label was added to a version of the
        prompt.

        - `PROMPT_VERSION_UNLABELED` — a label was removed from a version of the
        prompt.

        - `EVALUATOR_VERSION_CREATED` — a new version of the evaluator was
        created.


        Prompt events are valid only for `PROMPT` sources, and evaluator events

        only for `EVALUATOR` sources.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: <api-key>
      description: >
        Most Arize AI endpoints require authentication. For those endpoints that
        require authentication, include your API key in the request header using
        the format

        ``` Authorization: Bearer <api-key>

        ```

````