Messages (Anthropic)

Compatible with the Anthropic Messages API. Anthropic SDKs and Claude Code use https://upupkey.com as the base URL (without /v1; the SDK adds it).

Example request

Common parameters

Counting tokens

Takes the same body as Messages (without max_tokens) and returns {"input_tokens": 123}.

Calling non-Claude models

The Messages API can call other vendors' models too — set model to deepseek-chat, for example. The gateway converts the format, which is how models such as DeepSeek and Qwen work inside Claude Code.