Batches API Reference

def create(
    self,
    *,
    requests: list[MessageBatchIndividualRequest],
    **kwargs
) -> MessageBatch:
    """
    Create a batch of message requests.

    Parameters:
        requests: List of individual message requests with custom_id

    Returns:
        MessageBatch with id, processing_status, request counts
    """
    ...

async def create(...) -> MessageBatch: ...

def retrieve(
    self,
    message_batch_id: str,
    **kwargs
) -> MessageBatch:
    """Retrieve batch status and metadata."""
    ...

async def retrieve(...) -> MessageBatch: ...

def list(
    self,
    *,
    before_id: str = NOT_GIVEN,
    after_id: str = NOT_GIVEN,
    limit: int = NOT_GIVEN,
    **kwargs
) -> SyncPage[MessageBatch]:
    """List batches with pagination."""
    ...

def list(...) -> AsyncPage[MessageBatch]: ...

def cancel(
    self,
    message_batch_id: str,
    **kwargs
) -> MessageBatch:
    """Cancel a batch in progress."""
    ...

async def cancel(...) -> MessageBatch: ...

def delete(
    self,
    message_batch_id: str,
    **kwargs
) -> DeletedMessageBatch:
    """Delete a batch."""
    ...

async def delete(...) -> DeletedMessageBatch: ...

def results(
    self,
    message_batch_id: str,
    **kwargs
) -> JSONLDecoder[MessageBatchIndividualResponse]:
    """Stream batch results as JSONL."""
    ...

def results(...) -> AsyncJSONLDecoder[MessageBatchIndividualResponse]: ...

class MessageBatch(BaseModel):
    """Batch metadata and status."""
    id: str
    type: Literal["message_batch"]
    processing_status: Literal["in_progress", "canceling", "ended"]
    request_counts: MessageBatchRequestCounts
    ended_at: str | None
    created_at: str
    expires_at: str
    cancel_initiated_at: str | None
    results_url: str | None

class MessageBatchRequestCounts(BaseModel):
    """Request count statistics."""
    processing: int
    succeeded: int
    errored: int
    canceled: int
    expired: int

class MessageBatchIndividualRequest(TypedDict):
    """Individual request in batch."""
    custom_id: str
    params: MessageCreateParams

batch = client.messages.batches.create(
    requests=[
        {
            "custom_id": "request-1",
            "params": {
                "model": "claude-sonnet-4-5-20250929",
                "max_tokens": 1024,
                "messages": [{"role": "user", "content": "What is AI?"}]
            }
        },
        {
            "custom_id": "request-2",
            "params": {
                "model": "claude-sonnet-4-5-20250929",
                "max_tokens": 1024,
                "messages": [{"role": "user", "content": "What is ML?"}]
            }
        }
    ]
)
print(f"Batch ID: {batch.id}")

batch = client.messages.batches.retrieve("batch_abc123")
print(f"Status: {batch.processing_status}")
print(f"Succeeded: {batch.request_counts.succeeded}")
print(f"Errored: {batch.request_counts.errored}")

import time

while True:
    batch = client.messages.batches.retrieve(batch_id)
    if batch.processing_status == "ended":
        break
    time.sleep(60)

results = client.messages.batches.results("batch_abc123")

for response in results:
    if response.result.type == "succeeded":
        print(f"{response.custom_id}: {response.result.message.content[0].text}")
    elif response.result.type == "errored":
        print(f"{response.custom_id}: Error - {response.result.error.message}")