Choose the payment experience you want to build, then follow its integration guide. Start in a sandbox so you can test payments without moving real money.
Choose your integration
Accept payments online
| You want to… | Start with |
|---|---|
| Send customers to a ready-made payment page | Hosted Checkout — create a checkout on your server and redirect the customer to SumUp. |
| Keep checkout on your website | Payment Widget — embed SumUp’s payment form and let it collect payment details. |
| Offer an accelerated wallet checkout | Swift Checkout — add Apple Pay and Google Pay to your website. |
| Add payments to an e-commerce platform | Plugins — use an integration for WooCommerce, PrestaShop, Wix, Medusa, or Vendure. |
For a first website integration, start with Hosted Checkout. Choose the Payment Widget when you need an embedded form. To charge returning customers, build on the widget with saved cards and recurring payments.
Accept payments in person
| You want to… | Start with |
|---|---|
| Control a card reader from a native mobile app | Reader SDKs — integrate payment acceptance into your Android or iOS app. |
| Start reader payments from a backend, web app, or desktop POS | Cloud API — control a reader through HTTPS requests. |
| Accept contactless payments without a separate reader | Tap to Pay — use a compatible phone and the SDK for your platform. |
The in-person quickstart walks through setup and your first payment. Check reader compatibility and market availability before choosing hardware or an SDK.
Set up a sandbox
Create a developer account(Opens in a new tab) to start with a sandbox merchant account. If you already have a SumUp account, create a sandbox merchant in Developer Settings.
Use the sandbox merchant’s credentials and merchant code when testing. For native SDK login, follow the merchant account setup guide to make sure you sign in to the sandbox merchant.
You can try Cloud API pairing and payments without a physical reader using Virtual Solo.
Choose your credentials
- Your own merchant account: use an API key for server-to-server API calls.
- Other merchants connect to your application: use OAuth 2.0 so each merchant can grant access.
- In-person integrations: follow your integration guide to configure an affiliate key and any required permissions. An affiliate key identifies your integration; it does not replace API authorization or SDK merchant login.
Keep secret API keys and OAuth client secrets on your server. Create online checkouts there, then let Hosted Checkout, the Payment Widget, or an SDK collect payment details.
Make your first test payment
Follow your chosen integration guide, then use the online payment testing guide or in-person payment testing guide to test successful payments, declines, and cancellation.
Use a unique reference for each payment attempt. Verify the final payment result before fulfilling an order, and handle repeated callbacks without fulfilling the same order twice.
For backend API calls, use a server-side SDK or explore the API reference. If you work with a coding assistant, set up SumUp skills and MCP tools to give it current integration guidance.