Stripe → QuickBooks Payment Sync: A Production Architecture

Stripe sends webhooks at-least-once, retries on failure, and may arrive out of order. QuickBooks's API has tight rate limits and rejects duplicates only sometimes. Without idempotency, you end up with double-posted payments or missing refunds.

We document a queue-based architecture using deduplication keys derived from Stripe event IDs, an outbox pattern for downstream QuickBooks calls, and the reconciliation job that catches anything the realtime path missed.