Senior MERN Developer (React.js + Node.js)
The Role:
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. 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
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.
- 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 optimization (virtualization, code splitting, Web Vitals).
- 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.
- Strong commitment to test-driven development using frameworks like Jest, React Testing Library, and Cypress, alongside hands-on experience with Docker, CI/CD pipelines (GitHub Actions), and AWS cloud services.
- Time zone: CET (+/- 3 hours). We are unable to consider applications from candidates in other time zones.
Nice-to-have:
- Experience with Next.js or Remix for production-grade full-stack React frameworks.
- Familiarity with relational databases (PostgreSQL, MySQL) alongside MongoDB.
- Experience with vector databases or AI model integration into Node.js backend services.
- Exposure to micro-frontends or monorepo setups (Turborepo, Nx).
Responsibilities:
- Design, develop, and deploy scalable full-stack features from initial database schema creation down to polished, pixel-perfect React interfaces.
- Build secure, high-concurrency microservices and web services, managing integrations with third-party APIs, webhooks, and real-time communication channels.
- Audit, profile, and optimize application throughput—reducing bundle sizes and rendering overhead on the front end while optimizing database queries and caching layers (Redis) on the back end.
- Lead architectural discussions, write modular and well-documented TypeScript code, enforce strict testing protocols, and conduct thorough peer code reviews.
- Collaborate with cloud and DevOps engineers to containerize applications, set up automated deployment pipelines, and maintain system monitoring tools.
What we offer:
Get paid, not playedNo more unreliable clients. Enjoy on-time monthly payments with flexible withdrawal options. Predictable project hoursEnjoy a harmonious work-life balance with consistent 8-hour working days with clients. Flex days, so you can rechargeEnjoy up to 24 flex days off per year without losing pay, for full-time positions found through Proxify. Career-accelerating positions at cutting-edge companiesDiscover exclusive long-term remote positions at the world's most exciting companies. Hand-picked opportunities, just for youSkip the typical recruitment roadblocks and biases with personally matched positions. One seamless process, multiple opportunitiesA one-time contracting process for endless opportunities, with no extra assessments. CompensationEnjoy the same pay, every month with positions landed through Proxify.Skills
- express
- restful
- jwt
- postgresql
- turborepo
- javascript
- cypress
- aws
- react
- node
- jest
- mysql
- ai
- docker
- mongodb
- remix
- github
- typescript
- graphql
- redux
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