Serhii M.

Backend engineer building production fintech systems live payments, multi-tenant SaaS, API integrations that run 24/7. Currently leading backend on a BNPL platform: FastAPI + PostgreSQL + Redis, processing MTN MoMo payments, Angaza device sync, credit scoring webhooks, React admin dashboard. 2000+ tests, Docker/CI/CD, deployed on AWS. What I build: - FastAPI backends with async architecture - Payment integrations (MTN MoMo, PayFast, Stripe) - Multi-tenant SaaS with RBAC and audit logging - Background processing pipelines with retry logic - Docker, AWS deployments, CI/CD infrastructure - React + TypeScript dashboards Stack: Python, FastAPI, PostgreSQL, SQLAlchemy, Redis, Docker, AWS, React, TypeScript I own problems end-to-end - from architecture to deployment. Code that doesn't break at 3 AM. Keywords: FastAPI developer, payment gateway integration, Stripe integration, MTN MoMo integration, webhook handler, idempotent API design, REST API developer, PostgreSQL backend, multi-tenant SaaS, RBAC, background job processing, Docker deployment, AWS EC2, CI/CD, fintech backend engineer, credit scoring API integration, KYC integration, audit logging