Mollie x QuickBooks Integration

The QuickBooks Mollie bank feed sat on the same product architecture as the Sage variant, but QuickBooks demanded its own auth, payload, and reconciliation semantics.

Shipping both meant keeping a shared shell while treating each integration contract on its own terms.

I owned the backend, frontend, and QuickBooks integration work: OAuth flows, webhook handling, and the mapping rules that kept financial sync repeatable under retries.

Where vendor behaviour was inconsistent, I designed for idempotency and clear failure recovery rather than assuming clean documentation.

Mollie activity could flow into QuickBooks for reconciliation workflows, delivered as a distinct integration surface on the shared Mollie bank-feed platform.