Lead Fullstack Developer (React, Node.js, Next.js)

Blu Selection - Recruitment Agency; Madrid; Híbrido; EUR 70.000 - 90.000; Jornada completa

Descripción de la vacante

A recruitment agency in Madrid is seeking a Senior or Junior Full Stack Developer to join their team and work on a new web platform using modern JavaScript technologies. The successful candidate will collaborate with various stakeholders to design and develop high-quality features. Required qualifications include 3-5 years of experience, strong skills in React and Next.js, and a solid understanding of backend technologies. This role offers a full-time freelance mission and a competitive daily rate in a hybrid work environment.

Servicios

Fixed daily rate: €525 / day (senior) or €375 / day (junior)

3-month contract, renewable

Hybrid environment

Formación

• 3-5+ years of experience as a Full Stack or Front-End Engineer.
• Strong hands-on experience with React.js and Next.js.
• Advanced knowledge of JavaScript and TypeScript.

Responsabilidades

• Develop and maintain complex, data-heavy user interfaces using React and Next.js.
• Design and integrate REST APIs and WebSocket endpoints.
• Collaborate with Product, UX, and Data to deliver features end-to-end.

Conocimientos

React.js

Next.js

JavaScript

TypeScript

REST APIs

Node.js

Docker

CI/CD

Agile teamwork

Herramientas

Jest

Testing Library

Confluence

Descripción del empleo

We are looking for a Senior or Junior Full Stack Developer to join our team and contribute to the development of a new web platform built with modern JavaScript technologies.

You will collaborate closely with the Tech Lead, Product Owner, UX Designer, and Data team to design, develop, and deliver high-quality features within an agile environment.

This role requires strong expertise in front‑end engineering (React / Next.js), solid understanding of backend APIs, and the ability to write scalable, maintainable code.

Responsibilities

• Develop and maintain complex, data-heavy user interfaces using React and Next.js
• Build and optimise reusable components and contribute to the internal UI library
• Design and integrate REST APIs and WebSocket endpoints
• Ensure code quality through clean architecture and best practices
• Write unit and integration tests (Jest / Testing Library)
• Collaborate with Product, UX, and Data to deliver features end-to-end
• Participate in architecture discussions and decision‑making
• Troubleshoot and resolve issues across the stack
• Contribute to CI / CD processes and development workflow improvements
• Maintain documentation on Confluence

Required Qualifications

• 3-5+ years of experience as a Full Stack or Front‑End Engineer
• Strong hands‑on experience with React.js and Next.js
• Advanced knowledge of JavaScript and TypeScript
• Experience building and consuming REST APIs
• Good understanding of backend technologies (Node.js required; Python / FastAPI is a plus)
• Experience with component libraries, design systems, or shared UI components
• Familiarity with modern testing frameworks (Jest, Testing Library)
• Good understanding of performance, security, and scalability principles
• Comfortable working in cross‑functional agile teams
• Strong communication skills in English

Nice to Have

• Experience with container technologies (Docker, AWS ECR / EKS, OpenShift)
• Experience with CI / CD pipelines
• Knowledge of SonarQube, Checkmarx, or similar code quality tools
• Experience in healthcare, pharma, or other regulated environments

What We Offer

• Full‑time freelance mission
• Fixed daily rate : €525 / day (senior) OR €375 / day (Junior)
• 3‑month contract, renewable depending on performance and roadmap
• Hybrid environment from Barcelona