PaymentKits guide · 7 min read
Build payment test fixtures your team can trust
Create a small, versioned set of synthetic inputs for cards, bank transfers, currencies and payment states.
Model states, not just happy paths
Include authorised, declined, pending, refunded, expired and duplicate events. The fixture names should make the user-facing outcome clear before anyone reads a payload.
Separate secrets from examples
Fixtures can document a signature header and a request body, but never hard-code production keys, real customer data or reusable access tokens. Keep any sandbox credentials in your team secret manager.
Make every fixture repeatable
Use deterministic IDs, fixed timestamps where possible, and a short README that explains the expected response. Repeatability turns a one-time debugging aid into a regression suite.