> ## Documentation Index
> Fetch the complete documentation index at: https://docs.omniakey.com/llms.txt
> Use this file to discover all available pages before exploring further.

# API Reference

> OmniaKey API reference for OpenAI-compatible, Anthropic-native, and Gemini-native protocols.

OmniaKey exposes three protocol surfaces on one API host. Start with the overview,
then choose the protocol your SDK or coding agent already speaks.

<CardGroup cols={2}>
  <Card title="API Overview" icon="book-open" href="/en/api/overview">
    Base URLs, endpoint matrix, model policy, and billing behavior
  </Card>

  <Card title="Authentication" icon="key" href="/en/api/authentication">
    API keys, headers, and SDK auth conventions
  </Card>

  <Card title="OpenAI-compatible API" icon="code" href="/en/api/openai-compatible">
    Chat Completions, Responses, and model list endpoints
  </Card>

  <Card title="Anthropic-native API" icon="message-square" href="/en/api/anthropic-native">
    Messages API for Claude Code and Anthropic SDKs
  </Card>

  <Card title="Gemini-native API" icon="sparkles" href="/en/api/gemini-native">
    Generate Content for Google Gen AI SDKs
  </Card>

  <Card title="Supported Models" icon="cubes" href="/en/models">
    Current Claude, GPT, and Gemini ids
  </Card>

  <Card title="Errors and Rate Limits" icon="triangle-alert" href="/en/api/errors">
    Status codes, quota errors, and troubleshooting
  </Card>

  <Card title="Balance and Usage" icon="chart-no-axes-column" href="/en/api/balance-usage">
    Prepaid balance, key caps, and usage records
  </Card>
</CardGroup>

## Public API scope

The public developer API currently documents these supported surfaces:

| Surface           | Supported today                                      |
| ----------------- | ---------------------------------------------------- |
| OpenAI-compatible | Chat Completions, Responses, Models                  |
| Anthropic-native  | Messages for Claude Code and Anthropic SDKs          |
| Gemini-native     | Generate Content and model discovery                 |
| Dashboard         | API keys, prepaid balance, key caps, usage analytics |

Image generation, audio, embeddings, rerank, fine-tuning, files, and batches are
not part of the current public OmniaKey documentation. If an upstream-compatible
path exists internally, do not treat it as a public capability until it appears
in this docs site and the dashboard model catalog.