Senior Frontend Engineer JavaScript, React & Native iOS Mobile Webellian Sp. z o.o. mazowieck

Technologies we use

• Type Script
• iOS
• Swift
• SwiftUI
• OAuth2
• JWT
• Tailwind CSS

As a Senior Frontend Engineer within Advanced Analytics, you will lead the design and development of user‑facing AI‑enabled products across web and mobile platforms. You will own the frontend layer of production applications — building sophisticated React‑based web interfaces and native iOS mobile experiences that bring AI capabilities directly to end users worldwide.

• 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 Test Flight 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 Dev Ops to integrate frontend build and deployment into CI/CD pipelines: web app deployments, iOS build automation (Fastlane), and release management.

• 6+ years of professional frontend development experience, with a strong track record of shipping production applications at scale.
• 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.

• Agile and Scrum practices.
• Clean Code, code quality measures, code review, documentation, issue tracking tools, testing environments.

• Private medical care, group insurance, life insurance.
• Hybrid work (at least 1 day/week on‑site) in Warsaw (Mokotów) with remote work opportunities.
• Opportunity to work with excellent professionals and an international team.
• High standards of work and focus on the quality of code.
• New technologies in use and continuous learning and growth.
• Sports and wellness support:
  Multisport card, shared sports activities, parking space for employees.
• On‑site recreation:
  Pinball, Play Station, video games, coffee, tea, and drinks.

I hereby authorize Webellian Poland Sp. z o.o. to process personal data provided in this document for the recruitment process pursuant to the Personal Data Protection Act of 10 May 2018 (Journal of Laws 2018, item 1000) and in agreement with Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46/EC (General Data Protection Regulation).