You can now test incremental authorisation end-to-end in the Sandbox environment - including authorised, declined, and failed increment outcomes - before going live.
Since we launched Incremental authorisation in February, the biggest gap was the ability to test it properly in Sandbox before integrating into production. That's now possible.
Sandbox support for incremental authorisation uses a delta-based trigger model: the outcome of each increment is determined by the difference between the amount you send in the increment request and the currently authorised amount at the time of the call.
Sequential increment behaviour
The delta is always calculated against the currently authorised amount - which only updates when an increment succeeds. After a failed or declined result, the base stays the same, so the same amount value will re-trigger the same outcome on your next attempt.
After a successful increment, the base shifts to the new total. Recalculate before your next test increment to get the outcome you want.
Get started
- Follow the Incremental authorisation guide - the sandbox section covers the full delta reference and sequential increment examples
- See the test cards reference for available Sandbox payment methods
- See the API reference for full request and response schemas