Backend Engineering Services - Fredrick Nyang'au

Tagline: Backend systems for real business problems.

I design and build backend systems, REST APIs, and payment integrations using Python, FastAPI, and PostgreSQL. Focused on clean schema boundaries, deterministic data flow, and practical problem-solving for businesses and technical teams in Kenya and East Africa.

What I Help With

• Backend & API Development: Modular FastAPI backends, PostgreSQL 16 schema design, raw SQL via asyncpg, numbered migrations, and Pydantic validation.
• M-Pesa / Daraja Integrations: STK Push, C2B webhooks, storage-layer idempotency via UNIQUE constraints, and background worker queues.
• Backend Fixes & Improvements: Query optimization with CTEs, eliminating race conditions, and hardening multi-tenant query isolation.

Problems I Help Solve

• Manual workflows running on spreadsheets and paper logs
• Payment reconciliation and delayed service activation
• External API integrations with structured error handling and timeouts
• Data and backend reliability enforced via PostgreSQL constraints
• Internal operational backends connecting business workflows

Relevant Engineering Work

Frixel Connect: WiFi & Fiber ISP Billing Platform

KukuFiti: Poultry Farm Management API

How I Work

Discover → Scope → Build → Verify → Handover

Discuss a project: Contact Fredrick Nyang'au or return to portfolio home.