Cancel a Message Batch

Changed on Oct 8, 2026

Batches may be canceled any time before processing ends. Once cancellation is initiated, the batch enters a canceling state, at which time the system may complete any in-progress, non-interruptible requests before finalizing cancellation.

The number of canceled requests is specified in request_counts. To determine which requests were canceled, check the individual results within the batch. Note that cancellation may not result in any canceled requests if they were non-interruptible.

Learn more about the Message Batches API in our user guide

post/v1/messages/batches/{message_batch_id}/cancel

Request

Base URL
https://api.anthropic.com
Auth
none declared

Path parameters

message_batch_idstring required

ID of the Message Batch.

Headers

anthropic-versionstring

The version of the Claude API you want to use.

Read more about versioning and our version history here.

anthropic-workspace-idstring

Optional header to select the Workspace for this request. The value is a Workspace ID (for example, wrkspc_011CZkZaBF1tNoB5wlCeusgy).

Only needed for credentials that can act on more than one Workspace. A credential that belongs to a specific Workspace may omit it; if sent, it must match that Workspace.

Response

Successful Response

archived_atstring date-time nullable required

RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

cancel_initiated_atstring date-time nullable required

RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

created_atstring date-time required

RFC 3339 datetime string representing the time at which the Message Batch was created.

ended_atstring date-time nullable required

RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

expires_atstring date-time required

RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

idstring required

Unique object identifier.

The format and length of IDs may change over time.

processing_status'in_progress' | 'canceling' | 'ended' required

Processing status of the Message Batch.

results_urlstring nullable required

URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

type'message_batch' required

Object type.

For Message Batches, this is always "message_batch".

Example response

{
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results"
}

Changes

Oct 8, 20265b6f4c063051 Revision changes
- breaking
  the response's property type changed from no type to object for status
- info
  added the optional property / to the response with the status
- info
  removed discriminator from response property for the response status
- info
  removed from the response property oneOf list for the response status
- info
  added the required property / to the response with the status
- info
  added the required property / to the response with the status
Sep 4, 20264789294140a2 Revision changes
- info
  added the new optional header request parameter anthropic-workspace-id
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status
- info
  added the non-success response with the status

Operation history