Chat API

Chat models are called by model name with one of three native protocols. Every model supports the OpenAI-compatible protocol. Claude models also support the Anthropic protocol, and Gemini models also support the Gemini protocol. Use the official SDK of each protocol and set its Base URL to https://api.get3w.com.

Protocol	Endpoint	Models
OpenAI	POST /v1/chat/completions	All chat models
Anthropic	POST /v1/messages	Claude models
Gemini	POST /v1beta/models/{model}:generateContent POST /v1beta/models/{model}:streamGenerateContent?alt=sse	Gemini models

Models

Provider	Model	Protocols
OpenAI	gpt-5.5, gpt-6-astra, gpt-6.1-sol	OpenAI
Google	gemini-3.1-flash-lite-preview, gemini-3.1-flash-lite, gemini-3.1-pro-preview, gemini-3.8-flash	Gemini, OpenAI
Anthropic	claude-opus-4.7, claude-opus-4.6, claude-fable-5.1, claude-opus-5.5	Anthropic, OpenAI
Alibaba	qwen3.7-max, qwen3.6-plus, qwen3.6-flash	OpenAI

GET /v1/models returns the same list, with a protocols array per model.

OpenAI

curl https://api.get3w.com/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.5",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Set "stream": true to receive Server-Sent Events. The stream ends with data: [DONE].

Anthropic

curl https://api.get3w.com/v1/messages \
  -H "x-api-key: YOUR_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-4.7",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

claude-fable-5.1 also accepts "channel": "economy" (default) or "official".

Gemini

curl "https://api.get3w.com/v1beta/models/gemini-3.8-flash:generateContent" \
  -H "x-goog-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{"role": "user", "parts": [{"text": "Hello"}]}]
  }'

For streaming, call :streamGenerateContent?alt=sse with the same body. The model is taken from the URL. Fields that only exist in Google's own API, such as safetySettings, cachedContent and built-in tools, are ignored when the request is served by an OpenAI-compatible supplier.

Authentication

All three protocols accept Authorization: Bearer YOUR_API_KEY. The Anthropic endpoint also accepts x-api-key, and the Gemini endpoints also accept x-goog-api-key or ?key=.

Billing

Each response includes a cost object (amount, currency) next to the protocol's own usage field (usage or usageMetadata). In streams, cost is on the last event that carries usage.

Next Steps

• How to List Models
• Error Codes