# Errors and pagination

## Errors

```json
{ "error": { "code": "not_found", "message": "Collection not found" } }
```

HTTP status codes: `400` bad request, `401`/`403` auth, `404` not found, `409` conflict (for example an order that is no longer fillable), `429` rate limited, `500` server error.

## Pagination

List endpoints accept `limit` (default 50, max 200) and return a `next` cursor when more results exist. Pass it back as `cursor`.

## Conventions

- Timestamps are Unix seconds in UTC.
- Amounts are strings in the smallest unit (wei) with a `decimals` field where relevant.
- Items are identified by `chain`, `contract` (checksummed) and `tokenId` (decimal string).
- Chains use the slugs listed in [Supported chains](/supported-chains).