Développeur Frontend React (H/F)

Job Description

As we continue to expand our digital products and strengthen our position as a leader in renewable energy technology, we are looking for an experienced React Front-End Developer to join our team.

We're looking for someone with a passion for building performant, scalable, and accessible web applications. You have solid experience developing and maintaining large React applications, enjoy solving complex technical challenges, and take pride in writing clean, maintainable code. Beyond delivering new features, you're motivated to continuously improve existing codebases, optimize performance, and promote front-end best practices.

At 3E, you'll work on meaningful products that help accelerate the global transition to renewable energy, collaborating with talented colleagues in an environment that values technical excellence, flexibility, and continuous learning.

You will join the frontend development team, which operates as a cross-functional product team, working closely with frontend and backend Developers, Product managers, and QA Engineers. You'll report to your team lead and collaborate regularly with the other teams to ensure technical alignment and deliver high-quality features.

As our new React Front-End Developer, you will help build and evolve our web applications written in React as part of a cross-functional product team.

Daily tasks involve:

• Develop, maintain, and evolve high-quality React/TypeScript applications, translating product and design requirements into robust, scalable, and maintainable features.
• Build and improve core product functionality in collaboration with product managers, designers, and backend engineers, ensuring a seamless and consistent user experience.
• Design and implement performant, data-heavy interfaces (e.g. dashboards, tables, and charts) capable of handling large and complex datasets efficiently.
• Identify, analyse, and resolve performance bottlenecks across the front-end using modern React optimisation techniques and best practices.
• Create and maintain reusable UI components within a shared design system (Material UI-based), ensuring consistency, accessibility, and scalability.
• Contribute to architectural decisions and continuously improve the structure, readability, and maintainability of the codebase.
• Participate in code reviews, promoting high engineering standards, clean code practices, and knowledge sharing within the team.
• Implement secure and reliable front-end patterns, including user authentication and role-based access flows where applicable.
• Collaborate in a multidisciplinary environment with developers, domain experts, and stakeholders to deliver impactful digital solutions in the renewable energy space.

Requirements

We are looking for a proactive team player who takes ownership of their work, asks the right questions early, and actively contributes to improving both the product and the team. Someone who communicates clearly and effectively with technical and non-technical stakeholders, making complex topics understandable and ensuring alignment across teams. Being pragmatic and quality-driven helps tremendously: you care about writing clean, maintainable code, but also know how to balance speed, impact, and long-term maintainability.

• You hold a University degree in Computer Science (or equivalent) and have 4+ years of Front-End experience (React focus).
• You are proficient in English (spoken and written).
• You are strong in React and TypeScript development.
• You are experienced in performance optimisation and debugging, and you know how to identify and resolve issues efficiently.
• You have experience working with existing codebases, including refactoring, improving structure, and building new features on top of legacy decisions.
• You understand UI/UX principles and build user-friendly interfaces.

Bonus points for:

• Other languages: you will have international colleagues speaking French, Dutch and other languages
• Experience with: Material UI (MUI) or similar component libraries/Redux Toolkit (RTK) for state management/frontend architecture patterns/Playwright for end-to-end testing and react testing library/Highcharts or similar data visualisation libraries/Nx and/or Vite as build frameworks (and monorepo setup)/linting and formatting tools (e.g. ESLint, Prettier)/Git, Docker and Azure DevOps pipelines.

Benefits

Our offices are hidden in the centre of Brussels with a view on a pond, with ducks and a heron bringing a regular visit. In addition to a stimulating atmosphere in a highly motivated group of people, 3E offers a unique opportunity to further develop yourself in a company/team with an ambitious growth plan, delivering innovative services.

Furthermore:

• Training on the job by our experts so you get to know our solution and work in and out
• Flexibility in our open-minded company.
• An international environment: projects in over 100 countries worldwide, colleagues of over 20 nationalities.

We are open to both independent contractors (commitment to 219 working days/year) or payroll contracts. For a Belgian payroll contract, the extralegal benefits are:

• Home working (2 days per week)
• Hospitalisation insurance
• pension saving
• ???9 meal voucher/day
• flexible income plan
• 20 legal days off + 12 compensation days (per full year worked)
• sustainable transport subscription or bike allowance (???0.36/km).