Proxify AB: Senior MERN Developer (React.js + Node.js)

The useful part

We are looking for a Senior MERN Stack Developer with heavy specialization in React.js and Node.js on behalf of one of our high-growth clients to architect, scale, and maintain high-throughput web applications. In this role, you will take operational ownership of both front-end user interfaces and back-end microservices, delivering seamless, secure, and responsive digital products. You will bridge user-facing features with complex database architectures and cloud infrastructure.

How it works

• You are a perfect candidate if you are growth-oriented, you love what you do, and you enjoy working on new ideas to develop exciting products.
• Strong commitment to test-driven development using frameworks like Jest, React Testing Library, and Cypress, alongside ha...
• Deep mastery of React internals, custom hooks, component design patterns, state management (Redux Toolkit, Zustand, or React Query), SSR/SSG frameworks (Next.js is a strong plus), and performance...
• What we are looking for: 5+ years of professional software engineering experience designing, building, and deploying end-to-end applications using MongoDB, Express.js, React.js, and Node.js.
• Deep proficiency in modern JavaScript (ES6+), TypeScript, asynchronous programming, event loops, and memory management across client and server environments.

What to take from it

Proven experience architecting scalable RESTful APIs, WebSockets, and/or GraphQL services. Proficiency with middleware design, authentication protocols (JWT, OAuth2, Passport.js), and event-driven architectures. Advanced knowledge of MongoDB schema design, aggregation pipelines, index strategy, performance tuning, and ORMs/ODMs like Mongoose or Prisma.

Details worth keeping

Sweden URL: http://career.proxify.io The Role: