Mohammad Sakawat H.

I rebuild business software that's already running the business — and wire AI into it where that actually pays. WinForms to web. Desktop to mobile. Legacy SQL to a real API. Without losing a row of live data — because the system can't stop while you modernize it. Most recent: a hotel group's Windows-only ERP on a production database holding years of posted financial transactions. I rebuilt it as an ASP.NET Core 9 API, an Angular admin suite, and a Flutter app for staff and guests — 19 modules (front desk, reservations, night audit, restaurant POS, inventory, accounts, HR, payroll), 500+ screens, a 127-report print engine, and a public booking engine with Stripe and local gateways. Shipped module by module. Zero downtime. Zero data loss. AI THAT ACTUALLY SHIPS Most "AI integration" work is a demo that never reaches production. I do the other kind: OpenAI and Claude API features built inside .NET applications that already have users, data and uptime requirements. → Document processing — invoices, POs, contracts, scanned forms into structured data your system can post → RAG over your own data — SQL Server, PDFs, ticket history, answered with citations staff can check → Natural-language query — a manager asks a question instead of waiting for someone to write a report → Workflow automation — classification, routing, summarisation inside .NET services The model was never the hard part. The plumbing is: auth, cost control, retries, keeping the model away from data it shouldn't see, validation before anything is written, and a fallback for when the API is down. That's the part most AI developers are missing — and it's where my 4,400 hours inside enterprise .NET codebases actually count. WHAT ELSE I BUILD → Legacy modernization — WinForms / VB.NET / DevExpress to ASP.NET Core + Angular → REST APIs — .NET 9, clean architecture, JWT auth, role and permission control → SQL Server — schema design, stored procedures, query tuning, versioned migrations applied safely against live production data → Mobile — Flutter (iOS + Android) on the same API; Kotlin native where needed → Reporting — dashboards plus pixel-exact printable reports accountants accept → Payments and integrations — Stripe, local gateways, email, WhatsApp, WordPress Domains I've shipped in: hospitality / PMS, ERP, inventory and procurement, accounting, order management, field service, manufacturing, internal tooling. TRACK RECORD $130k+ earned on Upwork across 4,500+ hours. 100% Job Success. Top Rated Plus. One client has kept me for four years and 3,800+ hours — I ship, and what I ship stays shipped. HOW I WORK I read your existing code before I quote. I'll tell you when a full rewrite is the wrong call and a staged migration is cheaper — or when a well-written query would do what you were about to spend money on AI for. No hand-holding needed on architecture. No disappearing mid-sprint. Send me the brief — what the system does today, what breaks, what you wish it did. I'll tell you straight whether I'm the right fit.