Credit Purchase & Top-Up Flow

End-to-end flow for purchasing credits in a SaaS application, from checkout initiation to credit balance update.

Flow Steps

User Initiates Purchase

Frontend

Create Stripe Checkout Session

Payment API

Redirect to Stripe Checkout

Stripe Checkout

Payment Success

Stripe

Webhook Received

Webhook Handler

Process Webhook

Webhook Processor

Update Credit Balance

Credit Service

Confirmation

Frontend + Email Service

Additional Edge Cases

Webhook arrives before user returns to app
Payment succeeds but webhook never arrives (polling fallback)
Partial refunds after credit usage
Chargeback handling

Failure Recovery

Webhook is source of truth. If webhook delayed, poll Stripe API for session status. All operations are idempotent. Failed payments don't affect credit balance. Support can manually adjust if needed.