# Batch
Source: https://docs.simpleserve.ai/docs/batch
Summary: Asynchronous inference for work that can wait. OpenAI Files and Batches, JSONL in and JSONL out, 24h or Flex window.
Availability: available
Last reviewed: 2026-08-25

### Create a JSONL file

One request per line with `custom_id`, `method`, `url`, and `body`. Every `url` in a file must match the batch's `endpoint`.

```json title="requests.jsonl"
{"custom_id": "request-1", "method": "POST", "url": "/openai/v1/chat/completions", "body": {"model": "qwen3.8-27b-batch", "messages": [{"role": "user", "content": "Summarize this text."}]}}
{"custom_id": "request-2", "method": "POST", "url": "/openai/v1/chat/completions", "body": {"model": "qwen3.8-27b-batch", "messages": [{"role": "user", "content": "Classify this ticket."}]}}
```

### Upload it

`POST /openai/v1/files` with `purpose: "batch"`. Each line is checked on upload. A bad line returns `400` with its line number. Files up to 200 MB.

**Python**

```python
file = client.files.create(file=open("requests.jsonl", "rb"), purpose="batch")
```

**JavaScript**

```ts
const file = await client.files.create({ file: fs.createReadStream("requests.jsonl"), purpose: "batch" });
```

### Create the batch

`completion_window` is always `24h`, as in the OpenAI API. Ask for the Flex tier through `metadata`. Endpoints: `/openai/v1/chat/completions`, `/openai/v1/completions`, `/openai/v1/embeddings`.

**Python**

```python
batch = client.batches.create(
    input_file_id=file.id,
    endpoint="/openai/v1/chat/completions",
    completion_window="24h",
    metadata={"tier": "flex"},
)
print(batch.id, batch.status)
```

**JavaScript**

```ts
const batch = await client.batches.create({
  input_file_id: file.id,
  endpoint: "/openai/v1/chat/completions",
  completion_window: "24h",
  metadata: { tier: "flex" },
});
console.log(batch.id, batch.status);
```

### Poll, then download

Read the batch until `status` is `completed`, then download `output_file_id`. Failed lines go to `error_file_id`.

```python
batch = client.batches.retrieve(batch.id)
if batch.status == "completed":
    content = client.files.content(batch.output_file_id).text
```

## Routes

| Route                                                                                                                                             | Purpose                  |
| ------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------ |
| `POST /openai/v1/files`, `GET /openai/v1/files`, `GET /openai/v1/files/{id}`, `GET /openai/v1/files/{id}/content`, `DELETE /openai/v1/files/{id}` | Input and output files.  |
| `POST /openai/v1/batches`, `GET /openai/v1/batches`, `GET /openai/v1/batches/{id}`, `POST /openai/v1/batches/{id}/cancel`                         | The OpenAI Batch object. |

## Batch states

| State         | Meaning                                                 |
| ------------- | ------------------------------------------------------- |
| `validating`  | Input file is being checked.                            |
| `in_progress` | Requests are running.                                   |
| `finalizing`  | Output file is being written.                           |
| `completed`   | `output_file_id` and `error_file_id` are ready. Billed. |
| `failed`      | Validation failed. `errors` is filled.                  |
| `expired`     | The completion window passed.                           |
| `cancelling`  | Cancel requested. Running requests finish.              |
| `cancelled`   | Cancel finished.                                        |

> **Retries**
> Failed requests are retried. You are billed once per completed request.

## Tiers and pricing

| Model | Model id | 24h tier per 1M tokens | Flex tier per 1M tokens |
| --- | --- | --- | --- |
| Qwen3.8 27B | `qwen3.8-27b-batch` | $0.22 | $0.15 |

| Tier | Request                      | Window                        |
| ---- | ---------------------------- | ----------------------------- |
| 24h  | `completion_window: "24h"`   | 24 hours.                     |
| Flex | `metadata: {"tier": "flex"}` | Up to 72 hours. Lowest price. |