Claude Platform Docs

Create a Message Batch

$ ant messages:batches create
POST/v1/messages/batches

Send a batch of Message creation requests.

The Message Batches API can be used to process multiple Messages API requests at once. Once a Message Batch is created, it begins processing immediately. Batches can take up to 24 hours to complete.

Learn more about the Message Batches API in our user guide

Parameters
--request: array of object{ custom_id, params }

Body param: List of requests for prompt completion. Each is an individual request to create a Message.

maxItems100000
minItems1
--user-profile-id: optional string

Header param: The user profile ID to attribute the requests in this batch to. Use when acting on behalf of a party other than your organization. Requires the user-profiles beta header. Applies to every request in the batch; an individual request whose user_profile_id body field conflicts with this header is errored.

--workspace-id: optional string

Header param: 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.

Returns
message_batch: object{ type: "message_batch", id, archived_at, 7 more }
type: "message_batch"

Object type.

For Message Batches, this is always "message_batch".

id: string

Unique object identifier.

The format and length of IDs may change over time.

archived_at: string

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

formatdate-time
cancel_initiated_at: string

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

formatdate-time
created_at: string

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

formatdate-time
ended_at: string

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.

formatdate-time
expires_at: string

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

formatdate-time
processing_status: "in_progress" or "canceling" or "ended"

Processing status of the Message Batch.

One of the following:
"in_progress"
"canceling"
"ended"
request_counts: object{ canceled, errored, expired, 2 more }

Tallies requests within the Message Batch, categorized by their status.

Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

canceled: number

Number of requests in the Message Batch that have been canceled.

This is zero until processing of the entire Message Batch has ended.

errored: number

Number of requests in the Message Batch that encountered an error.

This is zero until processing of the entire Message Batch has ended.

expired: number

Number of requests in the Message Batch that have expired.

This is zero until processing of the entire Message Batch has ended.

processing: number

Number of requests in the Message Batch that are processing.

succeeded: number

Number of requests in the Message Batch that have completed successfully.

This is zero until processing of the entire Message Batch has ended.

results_url: string

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.

Create a Message Batch
ant messages:batches create \
  --api-key my-anthropic-api-key \
  --request '{custom_id: my-custom-id-1, params: {max_tokens: 1024, messages: [{content: [{text: x, type: text}], role: user}], model: claude-opus-5}}'
Returns Examples
Response 200
{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "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",
  "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",
  "type": "message_batch"
}