Custom Integrations

Guides in this section cover the basics of SumUp APIs, allowing you to develop a custom integration if SumUp products don’t fully support your use case.

Getting a Sandbox Merchant Account

Create a sandbox merchant account to test APIs without real money:

1. Log in to your SumUp account.
2. Open Developer Settings(Opens in a new tab).
3. In the Sandboxes tab, create a sandbox merchant account if you do not have one yet.

Note

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.

A screenshot of the account selection dropdown in the SumUp dashboard with the sandbox merchant account highlighted with red circle

With your sandbox merchant account, begin making API calls with real data. Sandbox merchant accounts do not process transactions with real funds. The sandbox merchant account has a different ID and displays a clear warning. Requests with a value of 11 (in any currency) always fail by design, to test failed transaction scenarios.

A screenshot of the dashboard with sandbox merchant account selected

When finished experimenting with the sandbox merchant account, switch back to a regular account for business purposes.

SumUp provides official SDKs for Node.js, Go, Python, Java, PHP, .NET, and Rust — visit the SDKs overview page to choose the client that fits your stack.