Senior Front End Engineer Full-time, remote | Long-term collaboration | Start: ASAP
Engagement model: Monthly retainer Time zone overlap: CET ±2h
About the role: We’re looking for a Senior Front End Engineer with deep browser knowledge and strong architectural skills; You’ll join a team building secure, high-performance, and scalable interfaces from scratch or refactoring existing ones; This role combines performance engineering, clean UI architecture, and technical leadership;
Your responsibilities will include: ● Architecting and building modern user interfaces with JS/TS, HTML5, and CSS3; ● Choosing between vanilla JS and frameworks based on project needs and scale; ● Profiling, debugging, and optimizing JS execution, memory, and rendering; ● Leveraging devtools to diagnose bottlenecks (initial load, paint, runtime); ● Leading code reviews and mentoring engineers across levels; ● Translating UX and product ideas into maintainable and accessible UI code; ● Collaborating with design, backend, and product teams on complex challenges. ● Exploring and adopting new frontend technologies and security best practices.
What we expect from you: ● Expert knowledge of JavaScript (ES6+) and async patterns; ● Solid understanding of V8 engine internals, event loop, memory management; ● Deep knowledge of DOM, CSSOM, layout, paint, and browser rendering pipeline; ● Experience with browser storage (localStorage, IndexedDB) and security policies (SOP, CORS, CSP); ● Proven experience optimizing frontend performance (lazy loading, tree shaking, code splitting); ● Strong grasp of networking: HTTP/2/3, TCP/IP, DNS — and how it impacts FE; ● Framework fluency (React, Vue, Svelte, or Angular) — and knowing when not to use one; ● Accessibility-first and mobile-first mindset; ● Experience with testing (Jest, Cypress), bundlers (Webpack, Vite, esbuild), CI/CD; ● Ability to write clean documentation, give actionable feedback, and elevate code quality; ● 5+ years of experience shipping large-scale web applications.
Bonus points if you have: ● Experience with PWAs, service workers, advanced browser APIs; ● Built performance-critical apps used in high-traffic environments; ● Worked with design systems or UI component libraries; ● Experience with user event tracking and identity management.
You’re a great fit if you: ● Are passionate about web performance, browser internals, and UI architecture; ● Balance pragmatism with code elegance; ● Can drive frontend strategy while staying hands-on; ● Don’t just write features — you solve problems.
