Yassine B.

Senior/Tech Lead Frontend Engineer (10+ yrs) | Scalable Architecture · Web Performance · Security · PrestaShop I help product teams ship frontends that stay fast, secure, and easy to change as they grow. For more than 10 years I've built and led frontend work on platforms serving millions of daily users. I own everything from architecture decisions down to the details users feel, like Core Web Vitals, bundle size, and accessibility. Proven results On a high-traffic platform with millions of daily users, I led a team of 4 frontend engineers through a performance overhaul: Bundle size cut by 75% (817 KB → 208 KB) Total Blocking Time cut by 62% (130 ms → 50 ms) LCP improved by about 3 seconds (8 s → 3.7 s) Speed Index improved by 20%, and load time dropped from 1.2 s to 850 ms What I bring to your project Frontend architecture that scales. Modular React/Vue/TypeScript codebases, monorepos (Nx, Lerna), and micro-frontends. The goal is that new features ship faster over time, not slower. Performance engineering. Profiling and fixing real bottlenecks: rendering, hydration, code splitting, caching, and build pipelines (Vite, Webpack, Rollup). Security by default. Hardening against XSS and CSRF, Content Security Policy, safe auth and token handling, dependency auditing, and secure API integration. Code quality you can trust. TDD, with a testing strategy that covers unit, integration, and end-to-end tests (Jest, Testing Library, Cypress, Playwright). This is backed by CI/CD, so every release is predictable. Team leadership. Mentoring engineers, running code reviews, and setting the standards that keep a codebase consistent as the team grows. Full delivery ownership. Node.js, GraphQL and REST APIs, Docker, AWS, and Terraform. I can take a feature from design to production without handoff gaps. PrestaShop and e-commerce. Custom modules, theme development, performance tuning, and integrations for online stores. Clients have called me a "PrestaShop rockstar." How I work I don't just execute tickets. I review specifications, flag risks early, and suggest improvements before any code is written. I communicate clearly, document decisions, and leave codebases better than I found them. Several clients have kept working with me for over a year. What clients say "Perfection at its finest. Finally found a quality Freelancer on Upwork." Clara "Yassine suggested how to improve the specification of the module to make it even better. We work together already more than one year." – Andy "He is a Prestashop rockstar." – John Good fit if you need: a senior or technical lead for a new/existing frontend, a performance or security audit, rescuing a legacy codebase, migrating to a modern stack, or building and optimizing a PrestaShop store. Send me a message with your project details, and I'll reply with concrete first steps. Yassine BELKAID