Freelance Senior OR Junior Full Stack Developer - React / Next.js / Node.js - Barcelona

Jordan martorell s.l.; Barcelona; Presencial; EUR 40.000 - 60.000; Jornada completa

Descripción de la vacante

A dynamic tech company in Barcelona is seeking an experienced Front-End Engineer to develop and maintain complex user interfaces using React.js and Next.js. The role offers a full-time freelance contract with a 3-month renewable term based on performance. The ideal candidate will have extensive experience with REST APIs and backend technologies like Node.js. Strong English communication skills are essential, and familiarity with container technologies such as Docker is a plus.

Formación

• 3-5+ years of experience as a Full Stack or Front-End Engineer.
• Strong hands-on experience with React.js and Next.js.
• Good understanding of backend technologies; Node.js required.

Responsabilidades

• Develop and maintain complex user interfaces using React and Next.js.
• Ensure code quality through clean architecture and best practices.
• Collaborate with Product, UX, and Data teams to deliver features.

Conocimientos

React.js

Next.js

REST APIs

Node.js

Unit and integration tests (Jest, Testing Library)

Cross-functional teamwork

Communication skills in English

Herramientas

Docker

AWS ECR/EKS

CI/CD tools

Descripción del empleo

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
• 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
• 3-month contract, renewable depending on performance and roadmap

Barcelona | Blu Selection - Recruitment Agency