Welcome to OpenPAI - OpenPAI Docs

What is OpenPAI

OpenPAI (openp.ai) is an LLM API aggregation gateway built for developers and enterprises. Through a single, OpenAI-compatible interface you can seamlessly call all the major model providers — without registering separate accounts, managing multiple keys, or handling billing for each vendor.

Unified interface

Fully compatible with the OpenAI SDK, with native support for the Claude /v1/messages and Google Gemini formats.

Hundreds of models

OpenAI, Anthropic, Google, DeepSeek, Qwen, Midjourney, Suno, Cohere, Jina and more, continuously added.

Pay as you go

Transparent token-based billing, lower rates on cache hits, with top-ups and quota management.

High availability

Weighted multi-channel routing + automatic retries, so a single upstream outage won’t break your service.

Quickstart

Just three steps to send your first request in five minutes:

Pick a model

Browse available models on the Models page of the console, or see the Models overview to choose the right one.

Send your first request

Point your OpenAI SDK base_url at https://openp.ai/v1 and replace the API key with your OpenPAI key.

curl https://openp.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENPAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gemini-3.1-pro-preview",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Explore the docs

Quickstart guide

The full flow from sign-up to your first request.

Supported models

See every available model, its billing multiplier, and context window.

API reference

Request/response fields, error codes and examples for every endpoint.

Client integrations

Connect tools like Cherry Studio, LobeChat, Cursor and Dify.

Three native protocols

Beyond full OpenAI compatibility, OpenPAI also exposes native Claude and Gemini protocol endpoints, so you can switch upstreams without rewriting your application:

OpenAI-compatible

POST /v1/chat/completions Authorization: Bearer sk-...

Claude Messages

POST /v1/messages x-api-key: sk-...

Gemini native

POST /v1beta/models/{model}:generateContent x-goog-api-key: sk-...

Need help?

FAQ

Answers to common questions about top-ups, models, billing and errors.

​What is OpenPAI