# List checkpoints

Source: https://langbot.ai/docs/api/receipts/list-checkpoints

`GET /v1/receipts/checkpoints`

Signed chain heads, newest first.

**Auth.** None. Without a token the call is served as Free (the Free delay and request budget, shared per IP); send `Authorization: Bearer lb_…` for your plan's.

**Limits.** Counts against your plan's API requests (60, 600 or 3,000 a minute on Free, Builder and Standard).

## Parameters

### Query parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `source_id` | string | no | One source. |
| `event_id` | string | no | One event (`ev_…`). |
| `limit` | integer | no | Page size. 1 to 1000. Default `100`. |

## Request

**curl**

```bash
curl "https://api.langbot.ai/v1/receipts/checkpoints?limit=1"
```

**Python**

```python
from langbot import LangbotClient

async with LangbotClient() as lb:
    for c in await lb.checkpoints(limit=1):
        print(c["chain_seq"], c["signature"])
```

**TypeScript**

```ts
const res = await fetch("https://api.langbot.ai/v1/receipts/checkpoints?limit=1");
console.log(await res.json());
```

## Response

`200 OK`

```json
{
  "count": 1,
  "checkpoints": [
    {
      "id": "ckp_01M6G0585EVFAYCHCZ67DYCPMY",
      "event_id": "ev_kxtrumpsaynickname_27jan01",
      "chain_seq": 27326,
      "hash": "6f716958521e204e06672571bc7071c051244a76f1cd05d5d9d4799a58b1b901",
      "count": 27326,
      "created_at": 1793685889198,
      "key_id": "7c2794192d3cf5a0",
      "signature": "7rOINkcu7vPyFyyesSy5KQ4lh16MebkGh2xW9oJSUopFcA7Eq+Qgv1zx89TrISjrAfTpX3w1rKu7DiJo+Zr+DQ=="
    }
  ]
}
```

A real response from the API; long lists are cut to their first items.

## Errors

| Status | `code` | When |
|---|---|---|
| 401 | `token_invalid` | A token was sent and not recognised. Send a valid one, or none to call anonymously. |
| 422 | `validation_error` | A parameter failed validation; `detail[].loc` names it. |
| 429 | `rate_limited` | Over your request budget; wait `Retry-After` seconds. |

Every error body is `{"detail": …, "code": "…"}`; branch on `code`. All codes: [Errors](https://langbot.ai/docs/api#errors).