# Sandbox testing

`Environment.INTEGRATION` is Ratepay's sandbox, a real deployment of the Payments API that accepts test
transactions without moving real money. Use it to validate that your actual request payloads are accepted,
end to end, beyond what a mocked unit test can tell you.

## Getting credentials

Sandbox OAuth credentials (client id/secret) aren't self-service today, email `integration@ratepay.com` if
you don't already have a set for the INTEGRATION environment.

## Pointing the client at the sandbox


```java Java
RatepayClient client = RatepayClient.builder()
    .clientId(System.getenv("RATEPAY_CLIENT_ID"))
    .clientSecret(System.getenv("RATEPAY_CLIENT_SECRET"))
    .environment(Environment.INTEGRATION)
    .build();
```


```kotlin Kotlin
val client = RatepayClient {
    clientId(System.getenv("RATEPAY_CLIENT_ID"))
    clientSecret(System.getenv("RATEPAY_CLIENT_SECRET"))
    environment(Environment.INTEGRATION)
}
```

This is exactly the [quickstart](/docs/developer/sdk/getting-started/quickstart)'s client setup, only the environment and credentials differ from production.

## What sandbox testing is for (and isn't)

Run your real request-building code against `Environment.INTEGRATION` to catch:

- Payloads the API rejects that your local validation (or mocks) wouldn't have caught, like malformed
addresses, currency mismatches, unsupported payment-method combinations, and similar 400/422s.
- Whether a full authorize → capture → refund/cancel sequence behaves the way you expect against a real
backend, including realistic response shapes and timing.


It's not a substitute for the mocked unit tests in
[Unit testing the quickstart flow](/docs/developer/sdk/testing/unit-testing-the-quickstart-flow) - sandbox calls are real network
requests, so they're slower, require credentials and connectivity, and aren't suitable to run on every
build. A practical split: unit-test your logic against a mocked `RatepayClient` for fast, deterministic
coverage in CI, and run a smaller number of sandbox-backed integration tests (or a manual pre-release
checklist) to validate against the real API.

No local stub server option
You can't point the SDK at your own local mock HTTP server as an alternative to the real sandbox.