Karim S.

I am a Top Rated Plus Senior Full-Stack Engineer (100% Job Success, 6,200+ hours, $240K+ earned) trusted by *Upwork Enterprise clients* and fast-moving startups to architect, build, and scale production web applications. Over the past 5+ years—including multi-year engineering leadership roles for Enterprise EdTech and SaaS teams—I have taken complex products from initial architecture to thousands of active users using TypeScript, React, Next.js, Node.js, PostgreSQL, and AWS. What I can help you build and own end-to-end: - Frontend Architecture: Fast, accessible, and responsive web apps and interactive dashboards using React, Next.js, TypeScript, and Tailwind CSS - Scalable Backends & APIs: Reliable Node.js, Express, and NestJS services, RESTful & WebSocket APIs, and complex business logic - Cloud & Real-Time Systems: Event-driven pipelines and serverless infrastructure on AWS (Lambda, SQS, WebSocket API) backed by PostgreSQL or MongoDB - Production AI Workflows: Multi-provider AI integrations (OpenAI, Azure, Stable Diffusion), automated content pipelines, and custom LLM features - Core SaaS Infrastructure: Multi-tenant authentication, role-based access, billing/payment integrations, client portals, and internal admin tools Why teams keep me on long-term contracts: - Zero hand-holding: I translate product goals into clean technical specs, spot edge cases early, and own features from database schema to UI polish. - Clear, proactive communication: Rated 5.0 across 18 completed jobs with 9 client endorsements for clear communication and solution-oriented execution. - Production-grade code: Strong focus on type safety, performance, maintainability, and fast delivery. If you need a senior engineer who can step into your codebase and deliver reliably, send me a message with a brief overview of your project—or book a 30-minute consultation directly on my profile.