Frontend Web Developer

This role is suitable for a Middle-level Frontend Web Developer with around three or more years of professional experience. Required skills include HTML, CSS, JavaScript, React, Vue, or Angular, state management, SASS or LESS, Webpack or Vite, Git, RESTful APIs, GraphQL, responsive design, accessibility, and performance optimization. The candidate should be familiar with building reusable responsive interfaces, integrating APIs, collaborating with designers and backend developers, debugging cross-browser issues, and working in an agile environment.

How would you structure a reusable component architecture for a React application?

I would separate presentational components, feature components, and shared UI primitives, keeping responsibilities focused and interfaces well defined. I would also use composition, consistent naming, and a clear folder structure to improve maintainability and reuse.

When would you use Redux, Zustand, or local component state?

I would use local state for isolated UI concerns, Zustand for lightweight shared client state, and Redux when the application requires predictable state transitions, middleware, strong debugging tools, or a larger team-wide convention.

How do you optimize the performance of a web application?

I would measure performance first using tools such as Lighthouse and browser profiling, then address issues through code splitting, lazy loading, asset optimization, caching, memoization where appropriate, and minimizing unnecessary renders and network requests.

How would you implement responsive design for different screen sizes?

I would use a mobile-first approach with flexible layouts, CSS Grid or Flexbox, relative units, and carefully chosen media queries. I would validate the implementation across representative viewport sizes and real devices rather than relying only on a single desktop browser.

What steps do you take to make a web interface accessible?

I use semantic HTML, correctly associated labels, keyboard navigation, visible focus states, sufficient color contrast, and appropriate ARIA only when native elements are insufficient. I also test with automated accessibility tools and manual keyboard and screen-reader checks.

How would you integrate a REST or GraphQL API into a frontend application?

I would define clear data-fetching boundaries, handle loading, error, empty, and success states, and validate or normalize responses when necessary. I would also consider caching, request cancellation, authentication, retries, and avoiding duplicate requests.

How do you handle cross-browser compatibility issues?

I start with standards-based HTML, CSS, and JavaScript, then use progressive enhancement and appropriate fallbacks for unsupported features. I test critical flows in the browsers and devices supported by the product and investigate issues using browser developer tools.

What is the role of Vite or Webpack in a frontend project?

Build tools transform, bundle, and optimize source code and assets for development and production. They can provide features such as hot module replacement, code splitting, environment configuration, tree shaking, and optimized output.

How would you debug a frontend issue reported by a user?

I would reproduce the issue, gather browser, device, network, and console information, and reduce it to the smallest failing case. After identifying the root cause, I would implement a focused fix, add or update tests, and verify it across affected environments.

How do you collaborate with designers and backend developers in an agile team?

I clarify requirements and edge cases early, agree on component behavior and API contracts, and communicate constraints or trade-offs proactively. I would contribute to refinement, review work through pull requests, and validate the final implementation against both design and technical requirements.

Air Apps is a self-funded, AI-focused company with over 100 million downloads, building tools that help people plan, work, and live more effectively. As a Frontend Web Developer, you’ll create responsive, accessible, high-performance interfaces, integrate APIs, and collaborate with designers, product managers, and backend engineers. The stack includes HTML, CSS, JavaScript, React/Vue/Angular, Redux/Vuex/Zustand, SASS/LESS, Vite/Webpack, REST, GraphQL, and Git. This is a fully onsite role in Lisbon with relocation support and compensation of €47K–€58K; apply to impact millions of users while enjoying excellent benefits, modern Apple hardware, and meaningful growth opportunities.