Payment Event Processor

Project Overview

The Payment Event Processor is a cloud-native payment infrastructure built to support multi-merchant SaaS platforms.

The system provides a centralized payment ledger, webhook processing engine, and merchant dashboard built on Stripe Connect, Google Cloud Run, Firestore, and event-driven architecture. The goal is to simplify the complex payment lifecycle for SaaS platforms.

Problem Statement & Solution

Platforms integrating payments face several challenges.

Payment Lifecycle Complexity

Payments involve multiple states including: authorization, capture, refunds, partial refunds, and disputes. Maintaining accurate financial records requires reliable event processing.

Solution: An event-driven webhook processing engine translates payment events into structured ledger updates in Firestore, maintaining a complete audit trail across the full lifecycle (authorization, capture, refunds, and disputes).

Stripe Webhook Complexity

Stripe generates dozens of event types including payment_intent events, charge events, dispute events, and refund events. Without proper infrastructure, webhook handling can lead to inconsistent states.

Solution: A centralized webhook endpoint normalizes supported Stripe events into consistent ledger mutations and guarantees idempotent processing, so events are never applied twice.

Multi-Tenant Platform Requirements

SaaS platforms must isolate merchant data while maintaining platform-level visibility. Requirements include: tenant isolation, merchant onboarding, compliance handling, and risk monitoring.

Solution: Stripe Connect keeps sensitive financial data isolated per merchant, while the platform enforces tenant isolation with authentication + RBAC and Firestore data-ownership checks. A risk engine provides exposure and payment-health metrics for both merchants and administrators.

Merchant Dashboard

The system includes a web-based dashboard where merchants can:

Administrators have access to a cross-tenant platform view.

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