curl -X POST 'https://api.anthropic.com/v1/messages/batches' \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H 'anthropic-version: 2023-06-01' \
  -H 'Content-Type: application/json' \
  -d '{
  "requests": [
    {
      "custom_id": "example-custom-id",
      "params": {
        "max_tokens": 1024,
        "messages": [
          {
            "content": "Hello, world",
            "role": "user"
          }
        ],
        "model": "claude-opus-5"
      }
    }
  ]
}'

# POST /v1/messages/batches (Claude API)
Base URL: https://api.anthropic.com
Auth: x-api-key; Anthropic API key; required.
Request formats: application/json.
Last verified: 2026-10-20

> Create a Message Batch

Keep the batch id from the response. Use it to [retrieve the batch](/anthropic/message-batches-retrieve) and check processing_status and request_counts. The results_url is null while processing; only when it is available after processing ends, [retrieve the results](/anthropic/message-batches-results). Match JSONL results to requests by custom_id. See the [Anthropic Create Message Batch reference](https://platform.claude.com/docs/en/api/http/messages/batches/create).

## Critical Gotchas
* Authentication uses the `x-api-key` header and requests also require an `anthropic-version` header.
* The official OpenAPI URL is discovered from the SDK repository manifest and must remain under Anthropic's trusted Stainless storage prefix.

## cURL
curl -X POST 'https://api.anthropic.com/v1/messages/batches' \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H 'anthropic-version: 2023-06-01' \
  -H 'Content-Type: application/json' \
  -d '{
  "requests": [
    {
      "custom_id": "example-custom-id",
      "params": {
        "max_tokens": 1024,
        "messages": [
          {
            "content": "Hello, world",
            "role": "user"
          }
        ],
        "model": "claude-opus-5"
      }
    }
  ]
}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| requests | body | object[] | Yes | List of requests for prompt completion. Each is an individual request to crea... |

## Response example
{"id":"msgbatch_013Zva2CMHLNnXjNJJKqJ2EF","type":"message_batch","processing_status":"in_progress","request_counts":{"processing":1,"succeeded":0,"errored":0,"canceled":0,"expired":0},"results_url":null}

---
Need an API key? Get one at https://console.anthropic.com/settings/keys

POST

POST /v1/messages/batches — Claude API

Anthropic API key (required); https://api.anthropic.com

Claude API

Create a Message Batch

Keep the batch id from the response. Use it to retrieve the batch and check processing_status and request_counts. The results_url is null while processing; only when it is available after processing ends, retrieve the results. Match JSONL results to requests by custom_id. See the Anthropic Create Message Batch reference.

Base URL: https://api.anthropic.com
Auth: x-api-key: <ANTHROPIC_API_KEY>
Last verified: 2026-10-20 · upstream hash matched

Actions Try in browser→

Agents: curl -H "Accept: text/markdown" this URL
→ 283 tokens · Vary: Accept

Critical gotchas

Authentication uses the x-api-key header and requests also require an anthropic-version header.

The official OpenAPI URL is discovered from the SDK repository manifest and must remain under Anthropic's trusted Stainless storage prefix.

cURL

curl -X POST 'https://api.anthropic.com/v1/messages/batches' \  -H "x-api-key: $ANTHROPIC_API_KEY" \  -H 'anthropic-version: 2023-06-01' \  -H 'Content-Type: application/json' \  -d '{  "requests": [    {      "custom_id": "example-custom-id",      "params": {        "max_tokens": 1024,        "messages": [          {            "content": "Hello, world",            "role": "user"          }        ],        "model": "claude-opus-5"      }    }  ]}'

Parameters

Name	In	Type	Required	Description
requests	body	object[]	Yes	List of requests for prompt completion. Each is an individual request to create a Message.

Response 200 OK

{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "type": "message_batch",
  "processing_status": "in_progress",
  "request_counts": {
    "processing": 1,
    "succeeded": 0,
    "errored": 0,
    "canceled": 0,
    "expired": 0
  },
  "results_url": null
}

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