# title: Retrieve a Message Batch url: https://platform.claude.com/docs/en/api/beta/messages/batches/retrieve

# Retrieve a Message Batch

GET /v1/messages/batches/{message_batch_id}

This endpoint is idempotent and can be used to poll for Message Batch completion. To access the results of a Message Batch, make a request to the results_url field in the response.

Learn more about the Message Batches API in our user guide

# Path parameters

message_batch_id: string

ID of the Message Batch.

# Headers

"anthropic-beta": optional array of AnthropicBeta

Optional header to specify the beta version(s) you want to use.
- string
- "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 43 more
  - "message-batches-2024-09-24"
  - "prompt-caching-2024-07-31"
  - "computer-use-2024-10-22"
  - "computer-use-2025-01-24"
  - "pdfs-2024-09-25"
  - "token-counting-2024-11-01"
  - "token-efficient-tools-2025-02-19"
  - "output-128k-2025-02-19"
  - "files-api-2025-04-14"
  - "mcp-client-2025-04-04"
  - "mcp-client-2025-11-20"
  - "dev-full-thinking-2025-05-14"
  - "interleaved-thinking-2025-05-14"
  - "code-execution-2025-05-22"
  - "extended-cache-ttl-2025-04-11"
  - "context-1m-2025-08-07"
  - "context-management-2025-06-27"
  - "model-context-window-exceeded-2025-08-26"
  - "skills-2025-10-02"
  - "fast-mode-2026-02-01"
  - "output-300k-2026-03-24"
  - "user-profiles-2026-03-24"
  - "user-profiles-2026-08-18"
  - "user-profiles-2026-09-04"
  - "advisor-tool-2026-03-01"
  - "managed-agents-2026-04-01"
  - "cache-diagnosis-2026-04-07"
  - "dreaming-2026-04-21"
  - "thinking-token-count-2026-05-13"
  - "server-side-fallback-2026-06-01"
  - "server-side-fallback-2026-07-01"
  - "fallback-credit-2026-06-01"
  - "fallback-credit-2026-07-01"
  - "agent-memory-2026-07-22"
  - "mid-conversation-tool-changes-2026-07-01"
  - "compact-2026-01-12"
  - "computer-use-2025-11-24"
  - "mcp-tunnels-2026-06-22"
  - "structured-outputs-2025-11-13"
  - "task-budgets-2026-03-13"
  - "thinking-display-updates-2026-08-18"
  - "ce-user-management-2026-07-13"
  - "mid-conversation-output-config-2026-07-01"
  - "thinking-binding-controls-2026-08-01"
  - "mid-conversation-system-clear-at-2026-08-21"
  - "compact-2026-09-04"
"anthropic-workspace-id": optional string

# Returns

BetaMessageBatch object
- type: "message_batch"
  
  Object type.
  
  For Message Batches, this is always "message_batch".
  
  default: message_batch
- id: string
  
  Unique object identifier.
  
  The format and length of IDs may change over time.
- archived_at: string or null
  
  RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.
  
  format: date-time
- cancel_initiated_at: string or null
  
  RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.
  
  format: date-time
- created_at: string
  
  RFC 3339 datetime string representing the time at which the Message Batch was created.
  
  format: date-time
- ended_at: string or null
  
  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.
  
  format: date-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.
  
  format: date-time
- processing_status: "in_progress" or "canceling" or "ended"
  
  Processing status of the Message Batch.
  - "in_progress"
  - "canceling"
  - "ended"
- request_counts: BetaMessageBatchRequestCounts
  
  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.
    
    default: 0
  - 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.
    
    default: 0
  - expired: number
    
    Number of requests in the Message Batch that have expired.
    
    This is zero until processing of the entire Message Batch has ended.
    
    default: 0
  - processing: number
    
    Number of requests in the Message Batch that are processing.
    
    default: 0
  - 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.
    
    default: 0
- results_url: string or null
  
  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.

# Example

bash

curl https://api.anthropic.com/v1/messages/batches/$MESSAGE_BATCH_ID \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

# Response (200)

json

{
  "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"
}

spb doc-api