FAQ

How do I create an Affiliate Key?

Open Developer Settings(Opens in a new tab) in the SumUp Dashboard, then go to For Developers > Toolkit > Affiliate Keys. Enter an application identifier that matches your app ID or bundle ID, then select Add.

An Affiliate Key identifies your card-present integration; it does not authorize API requests. Follow the Affiliate Keys guide for creation steps, credential requirements, and request examples.

How do I check completed transactions?

Our API provides endpoints where you can query transaction statuses, either for a single transaction or a list of transactions based on search criteria.

Can I get a sandbox merchant account?

To get started with SumUp, first log in(Opens in a new tab). If you don’t have a SumUp user account yet, register first. Then follow the Activate my account(Opens in a new tab) steps.

Once your user account is active, open Developer Settings(Opens in a new tab) and create a sandbox merchant account in the Sandbox environment section. Your sandbox merchant account is created for the same country as your live merchant account.

If you don’t have a sandbox account yet, sign up for a developer account(Opens in a new tab). This starts you with a sandbox merchant account.

Once your sandbox merchant account is created, copy and store the generated username (format: 32characters@developers.sumup.com) and unique password securely.

Note: You won’t be able to access the password again, so store it safely before dismissing the message.

Can I integrate SumUp to my website?

Yes, as a SumUp merchant you have the option to integrate SumUp’s eCommerce service with a webshop plugin or via direct integration.

SumUp’s official plugin supports integrations with WordPress/WooCommerce(Opens in a new tab).

For PrestaShop users we recommend this plugin(Opens in a new tab) developed by a SumUp partner.

For WIX users we recommend following their native solution(Opens in a new tab).

The direct integration option uses the SumUp Checkout API, intended for developer utilisation. All information can be found in our Online Payments section.

Note

For all webshop plugins and direct integration, make sure your merchant account is fully on-boarded before purchasing the plugin or starting the integration. Please share your client_id to activate the “Payments” scope through our contact form.

How do I set up OAuth credentials?

Open the OAuth apps page(Opens in a new tab) in the SumUp Dashboard and select Create application. After registering the application, open it and select Create client secret.

Follow the OAuth application registration guide for redirect URI, scope, and credential-storage requirements.

I'm receiving a "403" error with a "request_not_allowed" error message. What does this mean?

This error message indicates that the “payments” scope is not enabled for your application. Contact us through our contact form for activation assistance.

Which libraries are supported by SumUp?

SumUp maintains multiple SDKs and APIs to simplify your integration work across online and in-person payments.

Server SDKs

• JavaScript / TypeScript, Go, Python, Java, PHP, .NET, and Rust SDK guides cover server-to-SumUp API calls for online payments and remote Solo reader management through the Cloud API.
• Use these when you’re building checkout pages, recurring billing, or card-present integrations from a backend or platform that can make API requests.

Card-Present Integrations

• Android SDK(Opens in a new tab) and iOS SDK(Opens in a new tab) let you embed our reader experience inside native apps.
• Payment Switch provides Android and iOS URL schemes for launching the SumUp app. It is a legacy fallback for integrations that cannot use the native SDKs or Cloud API.
• See the terminal payments comparison before choosing an integration, then follow its canonical implementation guide.

Cloud API for Supported Readers

• The Cloud API triggers card-present transactions on supported readers from any backend or platform that can make HTTPS calls.
• Use it when your POS runs on web, desktop, or another environment that can’t embed the native Android/iOS SDKs but still needs in-person payments.

Which currency should I use for a payment?

Use the default currency of the merchant account receiving the payment. The currency in a checkout or reader-payment request must match that merchant account; it is not a per-transaction settlement-currency choice.

Currency availability depends on the merchant’s registered country and the product or payment method being used. For online payments, use a value accepted by the currency field in Create a Checkout and check payment-method availability for the merchant and checkout. For in-person payments, use the merchant account currency and confirm that the selected reader and integration are available in that market.

For a country-by-country reference, see Countries and Currencies. When building a payment request, do not derive the value from that table. Read the merchant account’s default_currency through the Retrieve a Merchant endpoint or from the SumUp Dashboard, and use that value.

Which operating systems support SumUp in-person integrations?

Platform support depends on the integration you choose:

• Cloud API works with web, desktop, and other server-capable platforms that can make HTTPS requests. The payment is completed on a supported reader.
• Terminal SDKs are available for native Android and iOS applications.
• Payment Switch supports Android and iOS app handoff as a legacy fallback.

Reader compatibility and market availability also vary. Use the in-person payments comparison and reader compatibility table before choosing a platform and reader.

I need help with a technical question.

Sure. You can reach us through our contact form.

Do SumUp card readers work in a standalone setup?

Some do. Solo has its own touchscreen and connectivity, so merchants can take payments without a paired phone or tablet. Other readers, such as Solo Lite, require a compatible companion device.

For a web-based, desktop, kiosk, or server-driven integration, use the Cloud API with a supported reader. If by “standalone” you mean an unattended or self-service deployment, confirm the requirements for your reader, market, and commercial setup with SumUp before implementation; standalone operation does not by itself establish suitability for unattended use.

Can my web app communicate with SumUp devices?

Yes. For a web-based or server-driven point of sale, use the Cloud API. Your backend makes authenticated HTTPS requests to start a payment on a supported reader, so the integration can run on any server-capable platform. Keep secret API keys out of browser code.

If a mobile web application must hand off the payment to the installed SumUp app, Payment Switch remains available as a legacy fallback. It is not the preferred path for new web integrations.

What is a sandbox merchant account?

SumUp sandbox merchant accounts mirror regular merchant accounts and follow the same rules. However, sandbox merchant accounts don’t connect to service providers and don’t process transactions with real funds.

Didn't find answer to your question? Contact us.