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

# Introduction

> Open-source, lightweight runtime telemetry for web apps — tiny error tracking in the browser, standard OpenTelemetry on the server, one normalized signal model, analyzed per repository.

Autter Runtime tracks **runtime errors and usage** from your frontend and backend. It deliberately does not ship the full OpenTelemetry browser SDK to your users:

* the browser gets a dependency-free, **\<5 KB** error and usage tracker
* your server keeps real OpenTelemetry
* Autter Runtime's **OTLP ingester** receives both and writes them to ClickHouse in a compact, per-repository data model

```mermaid theme={null}
flowchart TD
    A["@autter/runtime-browser (tiny tracker)"] --> B["Same-origin relay (@autter/runtime-node)"]
    B --> D["otlp-ingester /v1/browser (JSON)"]
    C["Server OpenTelemetry"] --> E["otlp-ingester /v1/traces + /v1/metrics (OTLP)"]
    D --> F["Normaliser + fingerprinter"]
    E --> F
    F --> G["ClickHouse (occurrences, spans, usage rollups)"]
    F --> H["Optional sink webhook → issue grouping"]
```

<Tip>
  Fastest way to get set up — let a coding agent do it:

  ```bash theme={null}
  npx skills add Autter-dev/autter-skills --all
  ```

  Then tell your agent: *"use the skills to install Autter Runtime in this
  project."* See [AI agent skills](/docs/runtime/skills) for details.
</Tip>

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/docs/runtime/quickstart">
    Go from zero to seeing data in ClickHouse in a few minutes.
  </Card>

  <Card title="Installation" icon="download" href="/docs/runtime/installation">
    Install the package for your stack — browser, Node, or Next.js.
  </Card>
</CardGroup>

## Packages

| Package                                                                                                      | Description                                                                                                           |
| ------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------- |
| [`@autter/runtime-browser`](https://github.com/Autter-dev/autter-runtime/tree/main/packages/runtime-browser) | Zero-dependency browser error + usage tracker (\~1 KB brotlied)                                                       |
| [`@autter/runtime-node`](https://github.com/Autter-dev/autter-runtime/tree/main/packages/runtime-node)       | Same-origin relay handler + curated OpenTelemetry server tracker                                                      |
| [`@autter/runtime-next`](https://github.com/Autter-dev/autter-runtime/tree/main/packages/runtime-next)       | One-command Next.js integration (relay route + error boundary)                                                        |
| [`@autter/otlp-ingester`](https://github.com/Autter-dev/autter-runtime/tree/main/packages/otlp-ingester)     | Self-hostable ingest service — OTLP/HTTP (protobuf + JSON) traces and metrics, plus browser payloads, into ClickHouse |

A runnable demo lives at [`examples/express-app`](https://github.com/Autter-dev/autter-runtime/tree/main/examples/express-app) — browser tracker → relay → ingester, and the OpenTelemetry server tracker, against a Docker Compose ClickHouse.

## Supported stacks

| Stack                              | How                                                  | Key type                             |
| ---------------------------------- | ---------------------------------------------------- | ------------------------------------ |
| React / any SPA / static site      | `@autter/runtime-browser` (direct)                   | client key (publishable)             |
| React/SPA with a backend           | `@autter/runtime-browser` → relay                    | none in browser; server key in relay |
| Next.js                            | `@autter/runtime-next`                               | server key                           |
| Node (Express, Fastify, Koa, Nest) | `@autter/runtime-node`                               | server key                           |
| Go, Rust, Python, Java, .NET, …    | any OpenTelemetry SDK → OTLP/HTTP (protobuf or JSON) | server key                           |

See [Stack integrations](/docs/runtime/integrations) for per-stack snippets, or [Using Autter Runtime without npm](/docs/runtime/without-npm) if your service has no `@autter/*` package at all.

## Keys: frontend vs. backend

Two credential types keep the frontend and backend cleanly separated:

|            | Server key (`autter_rt_…`)           | Client key (`autter_rtc_…`)                         |
| ---------- | ------------------------------------ | --------------------------------------------------- |
| Secrecy    | **secret** — backend env vars only   | **publishable** — safe in frontend bundles          |
| Can send   | OTLP traces/metrics + browser events | browser events only                                 |
| Protection | rate limits                          | origin allow-list + tighter rate limits, write-only |

<Tip>
  When your app has a backend, prefer the **relay**: the browser posts to your own server, which forwards with the server key. No key ever reaches the browser, and ad-blockers can't tell it apart from your own API traffic.
</Tip>

## Design principles

* **Errors are 100%, everything else is sampled or aggregated.** Raw error occurrences are always kept (14-day TTL); successful traces are expected to be sampled upstream (0.5–1%); usage is stored as 1-minute rollups (90 days).
* **Per-repository analysis.** Every row is keyed by `org_id` + `repository_id`.
* **Privacy by construction.** No cookies, no DOM, no request/response bodies, no emails, no full URLs with query strings.
* **OTLP-compatible at the ingestion layer**, not inside a 3 KB browser script.

Autter Runtime is open source under the MIT license: [Autter-dev/autter-runtime](https://github.com/Autter-dev/autter-runtime).