Senior Frontend Engineer [JavaScript, React & Native iOS Mobile]

Our requirements

• 6+ years of professional frontend development experience, with a strong track record of shipping production applications at scale.
• Expert-level JavaScript and TypeScript: deep understanding of the language, async patterns, module systems, and type-safe application design.
• Expert-level React: hooks, context, state management (Redux Toolkit, Zustand, or equivalent), performance patterns, and large-scale component architecture.
• Strong native iOS development skills using Swift and SwiftUI; experience with UIKit is a plus.
• Solid experience with iOS-specific concerns: push notifications, background processing, Keychain, deep linking, and App Store review guidelines.
• Experience consuming and designing frontend integrations with REST APIs, including authentication (OAuth2, JWT), error handling, and data caching strategies.
• Strong CSS and layout skills: responsive design, CSS-in-JS (Styled Components, Emotion), or utility-first frameworks (Tailwind CSS).
• Experience with frontend build tooling: Vite, Webpack, or equivalent; understanding of bundling, tree-shaking, and deployment optimization.
• Hands-on proficiency with Claude Code: using it daily for development, debugging, refactoring, and documentation tasks.
• Proven ability to define architecture, set standards, and lead technical decisions in a senior individual contributor or tech lead capacity.
• Strong communication skills: able to collaborate effectively with designers, product managers, and backend engineers across global, distributed teams.

Your responsibilities

• Architect and build production-grade React web applications: component design, state management, routing, performance optimization, and accessibility (WCAG compliance).
• Develop native iOS applications using Swift and SwiftUI (or UIKit where required), delivering high-quality, App Store-ready mobile experiences.
• Define and enforce frontend architecture standards: folder structure, component libraries, design system integration, and code quality conventions across web and mobile.
• Integrate frontend applications with REST APIs and event-driven backends, handling authentication flows, error boundaries, loading states, and real-time data patterns.
• Implement robust frontend testing strategies: unit tests (Jest, Vitest), component tests (React Testing Library), end-to-end tests (Playwright or Cypress), and iOS XCTest suites.
• Lead frontend performance engineering: bundle optimization, lazy loading, rendering strategies (SSR, CSR, ISR), Core Web Vitals, and iOS app performance profiling.
• Own the mobile development lifecycle on iOS: from Xcode project configuration and provisioning profiles to TestFlight distribution and App Store submission.
• Collaborate with UX Designers to translate designs into pixel-perfect, responsive, and accessible interfaces on both web and iOS.
• Champion AI-augmented development workflows using Claude Code: apply it actively for prototyping, code review, refactoring, and documentation generation.
• Conduct thorough code reviews, contribute to architectural decision records (ADRs), and mentor junior and mid-level frontend engineers.
• Work with DevOps to integrate frontend build and deployment into CI/CD pipelines: web app deployments, iOS build automation (Fastlane), and release management.

About the project

This is how we organize our work

This is how we work on a project

• Clean Code
• code quality measures
• code review
• documentation
• issue tracking tools
• testing environments

What we offer

• Contract under Polish law: B2B or Umowa o Pracę
• Benefits such as private medical care, group insurance, Multisport card
• English classes available
• Hybrid work (at least 1 day/week on-site) in Warsaw (Mokotów)
• Opportunity to work with excellent professionals
• High standards of work and focus on the quality of code
• New technologies in use
• Continuously learning and growth
• International team
• Pinball, PlayStation & much more (on-site)

Benefits

• sharing the costs of sports activities
• private medical care
• life insurance
• remote work opportunities
• fruits
• video games at work
• coffee / tea
• drinks
• parking space for employees
• leisure zone
• Pinball, PlayStation & much more
• English classes

Recruitment stages

• 1.
  📞A quick phone call with our Recruiter.
• 2.
  📅Online technical interview, testing your skills.
• 3.
  📅II face-to-face interview with your potential supervisor.
• 4.
  🗒️Feedback.

Webellian Sp. z o.o.