Mid-Level Frontend Engineer (React.js) - 4 Months - Remote

This role is suitable for a Mid-Level Frontend Engineer with 3–5 years of experience building and maintaining production web applications with React.js and Next.js.

The candidate should be skilled in JavaScript, TypeScript, HTML5, CSS3, responsive and accessible design, Tailwind CSS or Bootstrap, REST/GraphQL integration, state management, Git, testing, and frontend architecture.

They should be familiar with developing reusable UI components, optimizing performance and Core Web Vitals, troubleshooting production issues, collaborating in Agile cross-functional teams, and participating in code reviews and feature delivery.

How would you decide between server-side rendering, static generation, and client-side rendering in Next.js?

Use server-side rendering for frequently changing, request-specific data; static generation for stable content that benefits from fast delivery; and client-side rendering for highly interactive or user-specific sections. The choice should consider SEO, data freshness, performance, and caching requirements.

How would you optimize a React and Next.js application for Core Web Vitals?

I would optimize image sizes with Next.js Image, reduce JavaScript bundles through code splitting, minimize unnecessary re-renders, preload critical resources, and improve server response times. I would also use Lighthouse, browser performance tools, and Sentry or real-user monitoring to identify regressions.

How do you design reusable and accessible React components?

I define clear component APIs, keep components focused, and separate presentation from business logic where appropriate. I also use semantic HTML, keyboard navigation, proper labels, focus management, and ARIA attributes only when native HTML cannot provide the required behavior.

When would you use Redux Toolkit versus TanStack Query?

TanStack Query is well suited for server state such as fetching, caching, synchronizing, and updating API data. Redux Toolkit is better for predictable client-side state shared across multiple areas of the application, such as UI preferences, workflows, or complex local business state.

How would you handle data fetching and caching for a REST or GraphQL API?

I would centralize API access in typed services or hooks, handle loading, error, and empty states consistently, and use TanStack Query or an equivalent cache. For GraphQL, I would also manage query fragments, variables, normalized data where appropriate, and avoid requesting unnecessary fields.

How do you prevent unnecessary re-renders in React?

I first identify the cause using React DevTools Profiler rather than applying optimization blindly. Then I use appropriate component boundaries, stable props, memoization with useMemo or useCallback when beneficial, and efficient state placement to avoid re-rendering unrelated parts of the tree.

How would you structure a TypeScript React project for maintainability?

I would organize code by feature or domain, with colocated components, hooks, tests, types, and API logic where practical. I would use strict TypeScript settings, explicit interfaces for public APIs, shared design-system components, and consistent linting and formatting rules.

How would you test a React component using Jest and React Testing Library?

I would test behavior from the user’s perspective by rendering the component, querying accessible elements, simulating interactions, and asserting visible results. I would mock network boundaries when necessary, while avoiding tests that depend heavily on implementation details such as internal state or exact DOM structure.

How would you investigate a production frontend issue?

I would reproduce the problem, inspect logs and Sentry reports, review recent deployments, and use browser and network tools to isolate the failure. After identifying the root cause, I would add a regression test, deploy the fix through CI/CD, and monitor the relevant error and performance metrics.

What practices do you follow when collaborating through Git and code reviews?

I use focused branches and commits, keep pull requests small, and provide clear descriptions and testing notes. During reviews, I check correctness, accessibility, performance, maintainability, and test coverage, while addressing feedback constructively and resolving conflicts carefully.

Octopus by RTG is seeking a Mid-Level Frontend Engineer for a four-month, fully remote contract based in Cairo, building scalable, customer-facing web applications. You’ll develop responsive React.js and Next.js interfaces, integrate REST and GraphQL services, manage state with Redux Toolkit or TanStack Query, optimize performance, and collaborate with cross-functional teams. The stack includes JavaScript, TypeScript, Tailwind CSS, Jest, React Testing Library, Docker, Sentry, CI/CD, and optionally AWS; salary is not disclosed. Apply for the opportunity to work on modern production applications, contribute to frontend architecture, and strengthen your experience with a collaborative international team.