> This page is for version 2025-11-27 (default).
> For other versions, use one of these documentation indexes:
> - 2025-11-27 (default): https://docs.caesar.xyz/2025-11-27/llms.txt
> - 2025-08-08: https://docs.caesar.xyz/2025-08-08/llms.txt

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.caesar.xyz/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.caesar.xyz/_mcp/server.

# Errors

Caesar uses standard HTTP response codes to indicate success or failure of an API request.

Successful responses are indicated by a `2xx` status code. With client (you) errors, the API will return a `4xx` status code. With server errors (us), the API will return a `5xx` status code.

By default, **all successful requests return a `200 OK` response**, regardless of the HTTP method used (`GET`, `POST`, etc.). The body will contain the relevant resource or acknowledgement payload.

### HTTP Status Codes

| Status                        | When it happens                                              | Example `error`                                               |
| ----------------------------- | ------------------------------------------------------------ | ------------------------------------------------------------- |
| **200 OK**                    | Default for all successful requests.                         | *Varies by endpoint*                                          |
| **400 Bad Request**           | Your request is malformed or fails validation.               | `Body contains incorrect JSON type for field "compute_units"` |
| **401 Unauthorized**          | Missing or invalid API key in the `Authorization` header.    | `Missing API key`                                             |
| **404 Not Found**             | The resource doesn’t exist (e.g. unknown research ID).       | `Resource not found`                                          |
| **429 Too Many Requests**     | You exceeded rate limits (applies to `POST /research` only). | `Rate limit exceeded. Try again later.`                       |
| **500 Internal Server Error** | An unexpected error occurred on our side.                    | `An unexpected error occurred`                                |