Claude API access — Opus, Sonnet & Haiku

Use Claude through a standard OpenAI-compatible API. Call Claude Opus, Sonnet and Haiku with the same SDK you already use — and reach 470+ other models with the same key.

G0I gives you Claude through one unified endpoint. Whether you need Opus for deep reasoning, Sonnet for balanced speed, or Haiku for fast lightweight calls, it is one model field away.

What you get

Full Claude line — Opus, Sonnet and Haiku, including the latest versions.
OpenAI-compatible — call Claude with the OpenAI SDK; no Anthropic-specific rewrite needed. A native Anthropic endpoint is available too.
Streaming, tools, vision & long context — the features Claude is known for, fully supported.
One key, every model — mix Claude with GPT, Gemini and others in the same project.

Get started in three steps

1 · Create an accountSign up at g0i.ai and grab an API key in seconds — no card required to start.

2 · Change one linePoint your existing OpenAI SDK at https://g0i.ai/v1. Same request shape, same response shape.

3 · Call any modelSwap the model field to use GPT, Claude, Gemini, Llama, DeepSeek and 470+ others — one key, one bill.

Example request

curl https://g0i.ai/v1/chat/completions \
  -H "Authorization: Bearer $G0I_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"claude-opus-4-7","messages":[{"role":"user","content":"Explain quicksort"}]}'

Browse every Claude version in the model catalog.

Get your API key — start free →

Frequently asked questions

Which Claude models are available?
The full Claude line — Opus, Sonnet and Haiku — including current-generation versions, all via one API key.

Can I call Claude with the OpenAI SDK?
Yes. G0I exposes Claude through the OpenAI-compatible /v1/chat/completions endpoint, and also offers a native Anthropic-style /v1/messages endpoint.

Can I use Claude and GPT in the same app?
Yes — one G0I key reaches Claude, GPT, Gemini and 470+ other models. Switch by changing the model field.