---
url: /docs/api/anthropic-messages.md
---
# Anthropic Messages

`POST /v1/messages`

Anthropic Messages API compatible endpoint.

See [Anthropic's documentation](https://docs.anthropic.com/en/api/messages)
for the full request and response specification.

:::info

For compatibility with [Claude Code](/coding-agents/claude-code.html) and other
compatible agents, the `/v1/messages` endpoint also supports the `X-Api-Key`
header for authentication.
:::

## Request

```bash
curl https://hyper.charm.land/v1/messages \
  -H "x-api-key: sk-hyper-xxxxxxxxxxxxxxxxxxxxxxxx" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek-v4-pro",
    "max_tokens": 1024,
    "messages": [
      {"role": "user", "content": "Hello!"}
    ]
  }'
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `model` | string | yes | Model ID from [`/v1/models`](/api/list-models) |
| `max_tokens` | integer | yes | Max output tokens |
| `messages` | array | yes | Array of message objects |
| `system` | string or array | no | System prompt |
| `stream` | boolean | no | Set `true` for SSE streaming |

All standard Anthropic parameters are accepted.

## Response

```json
{
  "id": "msg_abc123",
  "type": "message",
  "role": "assistant",
  "content": [
    {"type": "text", "text": "Hey there!"}
  ],
  "model": "deepseek-v4-pro",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 10,
    "output_tokens": 5
  }
}
```

## Errors

All errors use the Anthropic error format:

```json
{
  "type": "error",
  "error": {
    "type": "...",
    "message": "..."
  }
}
```

| Status | `error.type` | Cause |
|--------|-------------|-------|
| 400 | `invalid_request_error` | Invalid JSON, missing `model`, `messages`, or `max_tokens`, context window exceeded |
| 401 | `authentication_error` | Missing or invalid `x-api-key` |
| 403 | `permission_error` | Forbidden |
| 404 | `not_found_error` | Model not found |
| 429 | `rate_limit_error` | Rate limit exceeded |
| 5xx | `api_error` | Upstream provider failure |