Mudasser Hassan · senior engineer
I'm Mudasser Hassan, a senior engineer in Lahore with 17+ years in C#/.NET and Java. Most of my work starts where a system is already running: third-party integrations that break in a new way every week, a codebase nobody left understands, a platform that has to stay up while it changes.
Backend, data and integrations are my depth. I take work end to end.
Focus
An upstream provider changes a field without telling you. A feed goes down and takes your pipeline with it. Two sources disagree about the same record. I build multi-source ingestion that survives all of it: canonical models where sources disagree, circuit breakers on flaky upstreams, change detection so you stop writing data that hasn't changed, and reconciliation for the records that don't line up.
Sometimes it's old — a .NET Framework application built by people who left years ago. Sometimes it's new — built fast with AI, shipped before anyone reviewed the architecture, working right up until it doesn't. The work is the same either way: an honest assessment first, stabilisation before modernisation, and a rewrite recommended only when a rewrite is genuinely cheaper. Usually it isn't, and I'll say so.
APIs and data layers that stay fast when the volume is real, and stay correct when the data isn't. Query performance, caching, partitioning, high availability, and the monitoring that tells you before your customers do.
Backend, data and integrations are my depth, but few clients want half a system. I take work end to end: the API and the data model, the React or Next.js front end on top of it, the mobile app that consumes it, and the deployment and monitoring that keep it alive.
Proof
I build the platform — CMS and API — behind live scores, fixtures, results and tables across a nine-title UK sports media network serving 25M+ monthly users, plus a national broadcaster's live centre and its mobile apps. It unifies 15+ upstream sources — automated APIs, scraping and manual editorial input — into one canonical model across 15+ sports, with high availability. I set the architecture and direct how the delivery and devops teams build and deploy.
Built end to end on my own: backend, web API and mobile API from a single codebase, serving web, iOS and Android. A statistical prediction engine with confidence scoring, real-time ingestion of third-party feeds, multi-dimensional filtering across dozens of competitions — a genuine query-performance problem at that traffic — personalised notifications, and Stripe subscription billing in production.
A Java service that ingests market data from 17 third-party providers — REST, XML and JSON, different cadences, varying reliability — into one canonical model. Five stages: normalise, map, validate, change-detect, persist. Hash-based change detection in Redis so only genuinely changed records are written, circuit breakers on every outbound provider, and multi-tier entity resolution that survives a provider renaming things mid-season.
Alongside these, I've raised data-quality accuracy on a live platform from 89% to 97% — removing over 1,000 hours of annual rework — and migrated legacy systems to modern stacks without taking the business offline.
Approach
If the first useful thing is telling you the problem isn't where you think it is, that's what you get — before anyone writes code.
I take a few at a time, so the ones I take get senior attention.
You deal with me, not a rotating cast. Where a piece of work needs a specialist — a senior front-end build, a native mobile app — I bring one in and stay responsible for what's delivered.
AI
I use AI throughout delivery, with review gates at every stage.
Engagement fit
Not a fit: training or fine-tuning models and data-science research — a different profession, and I'll say so rather than learn on your budget. Also not a fit: brand-first website builds, and high-volume commodity work.
Get in touch
Tell me what's breaking, or what you're afraid to touch. If a short paid audit is the right first step before committing to anything larger, I'll say so.