Backend engineer building billing and provisioning systems that stay reliable under load. Currently shipping production infrastructure at an ISP — payment processing, FreeRADIUS provisioning, real-time WebSocket feeds.

Production billing backend for an active ISP. Payment webhooks auto-provision subscribers to FreeRADIUS in 10–20 seconds. Redis-backed idempotent callbacks prevent double-provisioning. Real-time subscriber status via WebSocket.

Tech: Flask · PostgreSQL · Redis · FreeRADIUS · WebSocket · Docker
Impact: Activation time reduced from ~5 min → 10–20s · ~80% fewer manual steps

Face recognition attendance system with JWT auth, RBAC, and background task processing via Celery. Full test suite with pytest.

Tech: FastAPI · DeepFace · SQLAlchemy · MySQL · Redis · Celery
🔗 github.com/Sukooos/absen_backend

Historical bandwidth analytics, router controls, and real-time metric updates.

Tech: React · Flask · PostgreSQL · Redis

• 🔗 LinkedIn: linkedin.com/in/raja-zahran
• 💼 Upwork: upwork.com/freelancers/~01584aa2b81b83572c
• ✉️ Email: rajazahran4@gmail.com
• 🌐 Portfolio: sukooos.vercel.app

"Your backend shouldn't crash at midnight. I make sure it doesn't."