Anthropic Messages · Docs


Method and path	`POST /v1/messages`, relative to `https://api.inferbase.ai`
Purpose	The same router in Anthropic's dialect. An Anthropic SDK, or Claude Code, routes through Inferbase unchanged.
Authentication	API key as a bearer token. The SDK's default `x-api-key` header is not read; set the SDK's auth token.
Limits	As chat completions.

Setup

Point ANTHROPIC_BASE_URL at https://api.inferbase.ai, and pass the Inferbase key as the auth token.

python

from anthropic import Anthropic

client = Anthropic(auth_token="inf_your_api_key", base_url="https://api.inferbase.ai")

Request

model takes the same values as the OpenAI surface, auto included, so an Anthropic client can route. Tool loops work in both directions: tool_use and tool_result blocks, streamed tool calls as input_json_delta events, and cumulative usage with the cache split on message_delta. Images are accepted.

Not translated yet, and refused with a 400 naming the field rather than dropped: thinking, document blocks, and images inside a tool result.

A session is named with the X-Inferbase-Session header, since the Messages shape has no routing field.

Example

bash

curl https://api.inferbase.ai/v1/messages \
  -H "Authorization: Bearer inf_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "auto",
    "max_tokens": 256,
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Response

The Anthropic Messages shape. model names the model that served the request.

Errors

Errors use Anthropic's envelope on this path: {"type": "error", "error": {...}, "request_id": "..."}, with 400 for a malformed request as Anthropic answers it. The conditions are the same as on chat completions. See Errors.

Last updated September 10, 2026.

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