Sizwe Mthembu

I’m a frontend-focused Full-Stack Engineer who builds responsive, accessible UIs with React, HTML5, and CSS3—and backs them with production-ready Node.js/Express RESTful APIs. I enjoy turning complex business needs into clean end-to-end experiences, from UI delivery to API integration.

At KWV Holdings (remote-first), I designed and optimized React-based frontend solutions delivering 3 responsive web portals with 0 layout bugs, and I contributed to backend work using Node.js and Express.js—building secure RESTful APIs (including Paystack webhooks) with 0 transaction errors. I thrive in agile ceremonies and code reviews, keeping quality high through disciplined development and testing.

I also bring an AI-aware engineering mindset. Through evaluating AI-generated code in my work and on projects like S.AI-AGENT, I architected a smart context engine that evaluated and filtered AI outputs, improving response quality by 60% and integrating modular UIs with external LLM REST APIs while troubleshooting complex async performance issues.