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KiosAPI is a unified API gateway that gives you OpenAI-compatible access to a wide range of large language models — including GPT, Claude (Anthropic), and Gemini (Google) — through a single endpoint. Instead of juggling multiple accounts, keys, and SDKs, you point your existing tools at KiosAPI and let it handle the routing.

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Model Compatibility

KiosAPI exposes an OpenAI-compatible API, so you can use the official openai Python or Node.js SDK, langchain, litellm, or any other library built for the OpenAI API without changing your application logic. Set the base_url to the KiosAPI endpoint, supply your KiosAPI key, and your code works out of the box. KiosAPI also supports native Claude and Gemini endpoint formats, so you can integrate using whichever SDK or convention your project already uses.

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Authentication Methods

Each endpoint format expects your API key to be passed differently in the HTTP headers. Use the table below to match the correct auth header to the endpoint you’re calling.
Use the correct auth header for the endpoint you’re calling. For example, the Claude native endpoint (/v1/messages) expects x-api-key, not Authorization: Bearer. Sending the wrong header returns a 401 Unauthorized error.

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Official Documentation References

For deeper understanding of each API format, refer to the official provider documentation:

Authentication

Learn how to pass your KiosAPI key for each endpoint format.

API Base URL

Find the correct base URL and configure it in your SDK.