# Affiliate Keys

import { Steps } from '@astrojs/starlight/components';

SumUp uses Affiliate Keys to identify critical metrics such as Total Processing Volume coming through a Partner's integration. The key associates all merchant account users of the Affiliate Key with the partner, allowing SumUp to enforce agreed terms such as fast onboarding, revenue share, and transaction fees. For that reason, **Affiliate Keys are mandatory for card-present integrations**, such as:

- Mobile SDKs including Android SDK and [iOS SDK](/terminal-payments/sdks/ios-sdk/)
- [API Payment Switch](/terminal-payments/payment-switch/)
- [Solo API (Cloud API)](/terminal-payments/cloud-api/)

Affiliate keys are not an authorization mechanism. Use them together with either [API keys](/tools/authorization/api-keys/) or [OAuth 2.0](/tools/authorization/oauth/) depending on how your integration calls SumUp APIs.

## Create Affiliate Key

<Steps>

1. Log in to [your SumUp account](https://me.sumup.com).
2. Expand your user account menu and open **Settings**.
3. Go to **For Developers** > **Toolkit**.
4. Select **Affiliate Keys**.
   The page shows the **Application identifier** field if no key exists, or lists existing keys.
5. Enter the **Application identifier** matching the App ID/Bundle ID from your development project (such as `com.example.app`).
6. Select **Add**. The key is generated, and the App ID is assigned to it. You can add more App IDs to the key if you need to integrate more apps, but **the key itself is immutable**.

</Steps>

## Example Usage

The Solo Terminal API includes the Affiliate Key in the [Reader Checkout Request](https://developer.sumup.com/api/readers/create-checkout) under the affiliate section:

- `app_id`: This is the aforementioned application ID.
- `key`: This is the Affiliate key unique to each account and mandatory for every merchant in their checkout requests.

```json
{
  "affiliate": {
    "app_id": "your_application_id",
    "key": "your_affiliate_key"
  },
  "checkout": {
    "amount": 10.0,
    "currency": "EUR",
    "description": "Test Transaction"
  }
}
```

## What's Next?

Check the following resources to build your integration:

- [OAuth 2.0 App Registration Guide](/tools/authorization/oauth/#register-an-oauth-application)
- [iOS SDK Guide](/terminal-payments/sdks/ios-sdk/)
- [Android SDK Guide](/terminal-payments/sdks/android-sdk/)
- [PHP SDK Guide](/online-payments/sdks/php/)
- [React Native SDK](/online-payments/sdks/react-native/)
- [Cloud API for the Solo Card Reader](/terminal-payments/cloud-api/)