Sufail

Backend Developer at Nexotech (2025-10 – Present)

Full Backend Ownership: Independently architected and deployed backends for three production systems: grocery e-commerce, car wash booking, and multi-tenant CRM.
Frontend Integration: Assisted with building and integrating frontend components of the CRM with the APIs.
Payment Systems: Implemented Razorpay payment flows using atomic transaction blocks with isolated refund task callbacks via Celery.
Performance Engineering: Reduced p99 response times by 50% (7.5s to 3.7s) through optimized JOINs, strategic indexing, and custom serializers.
Realtime Architecture: Split the monolithic WSGI deployment into a sync REST tier (Gunicorn) and an async realtime tier (Uvicorn + Socket.IO) communicating via Redis Streams; replaced per-request async_to_sync broadcasts with a consumer-group pipeline that cut per-ping cost on the request thread ~50x and coalesced 5Hz GPS pings into 1Hz outbound emits with at-least-once delivery.
Spatial Query Optimization: Migrated location-based fetching to PostGIS spatial queries with GiST indexing, significantly reducing query latency.
Infrastructure & Observability: Set up Prometheus + Grafana monitoring, Redis caching with reusable decorators, and Sentry error tracking.
Advanced Query Patterns: Implemented recursive CTEs for hierarchical reporting and MPTT models for nested task structures.
Documentation & Collaboration: Produced flow-level API documentation beyond Swagger; collaborated closely with frontend teams for integration and debugging.

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