curl --request POST \
  --url https://api.arize.com/v2/webhook-subscriptions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "webhook_id": "V2ViaG9vazoxMjM0NQ==",
  "source_type": "PROMPT",
  "source_id": "UHJvbXB0OjEyMzQ1",
  "event": "PROMPT_VERSION_LABELED"
}
'

{
  "id": "V2ViaG9va1N1YnNjcmlwdGlvbjoxMjM0NQ==",
  "webhook_id": "V2ViaG9vazoxMjM0NQ==",
  "source_type": "PROMPT",
  "source_id": "UHJvbXB0OjEyMzQ1",
  "event": "PROMPT_VERSION_LABELED",
  "created_at": "2026-08-01T12:00:00Z"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

Webhooks

Create a webhook subscription

Subscribe a webhook to one event on a prompt, evaluator, evaluation task, or space. To deliver several events to the same webhook, create one subscription per event. A SPACE subscription covers every evaluation task in the space, including tasks created later.

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, evaluator events for EVALUATOR sources, and ONLINE_TASK_RUN_FAILED for ONLINE_TASK and SPACE sources. Other combinations are rejected with a 422.
An ONLINE_TASK source must be an evaluation task; other task types 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, EVALUATOR_UPDATE for an evaluator source, PROJECT_EVAL_TASK_UPDATE (or EXPERIMENT_EVAL_TASK_UPDATE for a dataset task) for a task source, or a space, organization, or account admin role for a space source, since a space subscription covers every task in the space, including tasks in restricted projects. Callers who can read the source (PROMPT_READ, EVALUATOR_READ, PROJECT_EVAL_TASK_READ or EXPERIMENT_EVAL_TASK_READ) but lack the required permission receive a 403; sources the caller cannot read yield a 404.

Checks run in this order, and the first failure is returned: request body validation (422), source access (404 or 403), source task type (422), webhook lookup (404), then duplicate subscription (409) and the per-source webhook limit (422).

This endpoint is in alpha, read more here.

POST

webhook-subscriptions

curl --request POST \
  --url https://api.arize.com/v2/webhook-subscriptions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "webhook_id": "V2ViaG9vazoxMjM0NQ==",
  "source_type": "PROMPT",
  "source_id": "UHJvbXB0OjEyMzQ1",
  "event": "PROMPT_VERSION_LABELED"
}
'

{
  "id": "V2ViaG9va1N1YnNjcmlwdGlvbjoxMjM0NQ==",
  "webhook_id": "V2ViaG9vazoxMjM0NQ==",
  "source_type": "PROMPT",
  "source_id": "UHJvbXB0OjEyMzQ1",
  "event": "PROMPT_VERSION_LABELED",
  "created_at": "2026-08-01T12:00:00Z"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

{
  "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"
}

Authorizations

Authorization

string

header

required

Most Arize AI endpoints require authentication. For those endpoints that require authentication, include your API key in the request header using the format

Body

application/json

Body containing the webhook, the source to attach it to, and the event to deliver

webhook_id

string

required

The unique identifier of the webhook to deliver the event to. Must belong to the source's organization.

Example:

"RW50aXR5OjEyMzQ1"

source_type

enum<string>

required

The kind of resource to attach the webhook to

Available options:

PROMPT,

EVALUATOR,

ONLINE_TASK,

SPACE

source_id

string

required

The unique identifier of the prompt, evaluator, evaluation task, or space to attach the webhook to

Example:

"RW50aXR5OjEyMzQ1"

event

enum<string>

required

The event to deliver. Must belong to the source type.

Available options:

PROMPT_VERSION_CREATED,

PROMPT_VERSION_LABELED,

PROMPT_VERSION_UNLABELED,

EVALUATOR_VERSION_CREATED,

ONLINE_TASK_RUN_FAILED

Response

The created webhook subscription

A subscription delivers one event from one prompt, evaluator, task or space to one webhook. A webhook that should receive several events from the same resource has one subscription per event.

string

required

Unique identifier for the subscription

Example:

"RW50aXR5OjEyMzQ1"

webhook_id

string

required

The unique identifier of the webhook that receives the event

Example:

"RW50aXR5OjEyMzQ1"

source_type

enum<string>

required

The kind of resource the subscription is attached to

Available options:

PROMPT,

EVALUATOR,

ONLINE_TASK,

SPACE

source_id

string

required

The unique identifier of the prompt, evaluator, evaluation task, or space the subscription is attached to

Example:

"RW50aXR5OjEyMzQ1"

event

enum<string>

required

The event delivered to the webhook

Available options:

PROMPT_VERSION_CREATED,

PROMPT_VERSION_LABELED,

PROMPT_VERSION_UNLABELED,

EVALUATOR_VERSION_CREATED,

ONLINE_TASK_RUN_FAILED

created_at

string<date-time>

required

Timestamp for when the subscription was created

Skills

MCP server

API reference

API clients

Create a webhook subscription

Authorizations

Body

Response