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

# SDK-less Integration

> Integrate Linkrunner on Android by calling the REST API directly, without the native SDK.

Linkrunner's native SDKs handle attribution for you. If you cannot add the Android SDK to your app, you can integrate the same way the SDK does: by calling Linkrunner's REST API directly from your app.

This section lists every endpoint the SDK uses, shows where to collect each signal on the device, and gives you ready-to-use client code for Android and iOS.

<Note>
  Use the [Android SDK](/sdk/android) when you can. It handles data collection, retries, and edge cases for you. Reach for SDK-less integration only when a policy, build constraint, or custom runtime stops you from adding the SDK.
</Note>

## How it works

<Steps>
  <Step title="Register the install">
    Call `init` with your token, the install instance ID, and device data. Linkrunner starts attribution in the background.
  </Step>

  <Step title="Read attribution">
    Poll `attribution-data` with the same install instance ID until campaign data appears.
  </Step>

  <Step title="Identify the user">
    Call `signup` when the user signs up or logs in. Events and payments are only stored for users who have been through `signup`.
  </Step>

  <Step title="Track activity">
    Send events and payments using the same install instance ID.
  </Step>
</Steps>

## Key concepts

### Project token

Every request is authenticated with your project token in the JSON body. That is the only credential these endpoints need. Find your token on the [dashboard](https://dashboard.linkrunner.io/dashboard?s=members\&m=documentation).

### Install instance ID

`install_instance_id` is a UUID your app generates once, stores, and sends on every request. It ties an install to the events, signups, and payments that follow.

**Generate it a single time and persist it** (`SharedPreferences` on Android, `UserDefaults` on iOS). If you create a new one per call, every request looks like a different device and attribution falls apart.

## Two things that break attribution

Get these right before anything else. Both fail silently.

| Rule                                                | Why it matters                                                                                                                                                                          |
| --------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Call the API from the device, not your backend.** | Linkrunner matches installs using the IP of the client that calls the API. If you proxy these calls through your server, every install shares one IP and matching fails.                |
| **Treat `init` as asynchronous.**                   | The `init` response never contains campaign data. Attribution runs in the background, so you read the result by polling [`attribution-data`](/sdk-less/api-reference#attribution-data). |

## Integrate on Android

<CardGroup cols={2}>
  <Card title="Full client (recommended)" icon="android" href="/sdk-less/android-quickstart">
    One Kotlin client that collects every signal and calls every endpoint. Closest to the real SDK.
  </Card>

  <Card title="Minimal example" icon="feather" href="/sdk-less/android-minimal">
    The smallest path that still attributes: install, signup, one event, one payment.
  </Card>
</CardGroup>

See [collecting device data on Android](/sdk-less/android-device-data) for where each field comes from.

## Integrate on iOS

<CardGroup cols={2}>
  <Card title="Full client (recommended)" icon="apple" href="/sdk-less/ios-quickstart">
    One Swift client that collects every signal, applies SKAdNetwork values, and calls every endpoint.
  </Card>

  <Card title="Minimal example" icon="feather" href="/sdk-less/ios-minimal">
    The smallest path that still attributes: install, signup, one event, one payment.
  </Card>
</CardGroup>

See [collecting device data on iOS](/sdk-less/ios-device-data) for where each field comes from.

## Reference

<CardGroup cols={1}>
  <Card title="API reference" icon="code" href="/sdk-less/api-reference">
    Every endpoint, with request and response bodies.
  </Card>
</CardGroup>

**Need help?** Contact [support@linkrunner.io](mailto:support@linkrunner.io)