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

# Welcome to Opper

> The AI gateway for agents. 300+ models through one EU-hosted gateway. Drop-in OpenAI, Anthropic, and Google AI SDK compatible. GDPR-compliant.

Opper is one API in front of every major AI model, hosted in the EU. Drop in your existing OpenAI, Anthropic, or Google AI SDK and keep your code — you get text, multimodal, and voice, plus observability, governance, and one sub-processor for every model.

<div style={{ background: 'linear-gradient(135deg, rgba(20,205,205,0.12), rgba(20,205,205,0.04))', border: '1px solid rgba(20,205,205,0.4)', borderLeft: '4px solid #14cdcd', borderRadius: '12px', padding: '1rem 1.25rem' }}>
  <div style={{ color: '#14cdcd', fontWeight: 700, marginBottom: '0.5rem' }}>Agent Assisted Development</div>

  ```
  Use curl to download, read and follow: https://skills.opper.ai
  ```

  <span style={{ fontSize: '0.85rem', opacity: 0.75 }}>Paste this into your coding agent — Claude Code, Cursor, Codex, and more — and it will set up and build with Opper for you.</span>
</div>

## Start here

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/overview/quickstart">
    Five minutes to your first call.
  </Card>

  <Card title="What is Opper?" icon="circle-info" href="/overview/about">
    The product tour: Gateway, Control Plane, and how they fit.
  </Card>

  <Card title="AI Gateway" icon="signs-post" href="/overview/gateway">
    One API, 300+ models, routing, and EU enforcement.
  </Card>

  <Card title="Security" icon="shield-check" href="/overview/security">
    Hosted in Stockholm. One sub-processor for every model. Store no logs at all if you need to.
  </Card>
</CardGroup>

## Build

<CardGroup cols={2}>
  <Card title="Drop-in SDKs" icon="plug" href="/build/gateway/drop-in-sdks">
    Use the OpenAI, Anthropic, or Google AI SDK you already have.
  </Card>

  <Card title="Structured output" icon="cube" href="/build/gateway/structured-output">
    Constrain any response to a JSON Schema. Great for parsing and extraction.
  </Card>

  <Card title="Realtime" icon="microphone" href="/build/realtime/quickstart">
    Two-way voice over WebSocket. OpenAI, xAI, and Gemini behind one protocol.
  </Card>

  <Card title="Models" icon="brain" href="https://opper.ai/models">
    The full catalog. EU-hosted models marked.
  </Card>
</CardGroup>

## Govern and improve

<CardGroup cols={2}>
  <Card title="Control Plane" icon="shield-check" href="/control-plane/overview">
    Five tools to govern, score, and improve every call.
  </Card>

  <Card title="Comply" icon="scale-balanced" href="/control-plane/comply">
    Restrict providers, regions, retention, and budget at the gateway.
  </Card>

  <Card title="Observe" icon="eye" href="/control-plane/observe">
    Score every response against criteria you write.
  </Card>

  <Card title="Concepts" icon="diagram-project" href="/overview/concepts">
    Calls, spans, traces, scopes. The mental model that ties everything together.
  </Card>
</CardGroup>