> ## 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.

# What is Opper?

> Opper is one connection to every AI model, with the tools you need to ship AI to real users.

Opper sits between your app and the AI models you use. One API key gets you 300+ models from every major provider, plus the observability and controls to run them in production.

Without it, you end up gluing the pieces together yourself: a separate SDK and key for each provider, and monitoring you add after something breaks. Opper is that whole layer behind one API. Switch models by changing a string, and every call is governed and metered by default.

## Build, observe, and control

<CardGroup cols={2}>
  <Card title="The Gateway" icon="bolt" href="/overview/gateway">
    One API for every model. Send a request, get a response. Switch models with a config change.
  </Card>

  <Card title="Observe & Control" icon="shield-check" href="/control-plane/overview">
    Inspect traces and manage checks, budgets, model access, and retention.
  </Card>
</CardGroup>

## The Gateway

One API that covers every modality and every major model.

* **Any model, same code.** Choose `openai/gpt-5.5`, `anthropic/claude-sonnet-4-6`, `gemini/gemini-2.5-pro`, or any of 300+ others by changing a string.
* **Beyond text.** Send images and PDFs in, and generate images, speech, and video, transcribe audio, and run realtime voice — all through the same API. See [Multimodality](/build/multimodal/overview).
* **Use your existing SDK.** Already on OpenAI, Anthropic, or Google AI? Point it at Opper and your code stays the same.
* **Or write no code at all.** Point an app you already use — Claude Code, Cursor, Zed, n8n — at Opper instead. See [Integrations](/integrations/overview).
* **One key.** Replaces a folder of provider credentials.

## Observe & Control

Once your AI is in front of real users, you need to understand what it is doing
and set clear operating boundaries. Opper lets you inspect calls and manage the
rules enforced by the gateway:

|                    | What it does                                                             |
| ------------------ | ------------------------------------------------------------------------ |
| **Data retention** | Sets how long request and response content is kept, or keeps none of it. |
| **Spend limits**   | Caps what an organization can spend in a calendar month.                 |
| **Model access**   | Limits which providers, regions, and models can be used.                 |
| **Checks**         | Scores responses against your criteria, and blocks or redacts content.   |
| **Route**          | Picks a default model for an app or feature.                             |

The first four live on the organization-level [Rules](/control-plane/rules/overview)
page. Each rule applies to the whole organization or selected projects. You can
review rule activity in traces when trace storage is enabled.

[Explore Observe & Control →](/control-plane/overview)

## Where Opper runs

Opper runs on AWS in Stockholm, and your data stays in-region. By default it stores only metadata, not your prompts or responses. Only the model call itself reaches the provider, and you can pin which providers and countries are allowed. The full picture is on the [Security](/overview/security) page.

## Get going

Run your first call, then read the Platform section in order to understand how it all fits.

<CardGroup cols={3}>
  <Card title="Quickstart" icon="rocket" href="/overview/quickstart">
    Five minutes to your first call.
  </Card>

  <Card title="Core concepts" icon="diagram-project" href="/overview/concepts">
    The mental model behind everything: planes, traces, scopes.
  </Card>

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