Senior Backend Engineer – Payment Platform Architecture Review

We’re looking for an experienced backend engineer to review the technical architecture of a planned B2B SaaS payment platform. Scope: Review the proposed Node.js/NestJS backend architecture. Review PostgreSQL multi-tenant data structure. Check API, webhook, and idempotency design. Review the planned document-processing workflow. Identify technical risks, gaps, and possible improvements. Provide a short written assessment with recommended next steps. Requirements: Strong Node.js/NestJS and PostgreSQL experience. Experience with APIs, webhooks, and SaaS architecture. Payment/fintech experience is a plus. Strong security and system-design knowledge. Deliverable: Short architecture review and recommendations.