Senior Frontend Developer ReactJS / Next.js – Freelance

Project overview

As part of the evolution and modernization of its digital platforms, our client is looking for a Senior Frontend Developer ReactJS / Next.js to strengthen its Web team.

You will work on a high-traffic public web portal, welcoming approximately 4 million visitors per week, in a context of evolutionary maintenance and technological migration.

The project is part of a gradual modernization of a platform historically developed in PHP/Symfony towards a ReactJS / Next.js architecture.

Integrated into an Agile team composed of developers, Product Owners, testers, and UX/UI Designers, you will actively participate in the design and development of the portal's features.

Responsibilities

Profile sought

You have confirmed senior experience in Frontend development, ideally between 3 and 10 years, with solid expertise in ReactJS and Next.js.

You have already participated in the development and maintenance of dynamic web platforms with a large audience.

You master the following technologies and environments:

Experience with technological migration projects, particularly from PHP/Symfony applications to ReactJS / Next.js, will be an asset.

You are recognized for your autonomy, your rigor, and your ability to produce quality code in a demanding technical environment.

You appreciate teamwork, know how to collaborate with a Tech Lead, and are comfortable in structured Agile organizations.

A good understanding of written English is also expected.

Work environment

You will join a stimulating technical environment, within an experienced team, and will directly contribute to the modernization of a major digital platform, with significant challenges in quality, reliability, and performance.

• Design and develop new web features in ReactJS, Next.js, JavaScript, and TypeScript.
• Participate in the progressive migration of existing pages from PHP/Symfony to ReactJS / Next.js.
• Ensure corrective and evolutionary maintenance of web applications.
• Develop reliable interfaces adapted to the constraints of a high-traffic public site.
• Participate in the technical design of features in collaboration with the Tech Lead.
• Write and maintain unit tests associated with developments.
• Participate in Agile ceremonies and contribute to the realization of User Stories.
• Ensure code quality and its integration into CI/CD processes.
• Perform code commits and merges in GitLab.
• Write technical documentation in Confluence and track developments in Jira.
• Frontend: ReactJS, Next.js, JavaScript, TypeScript.
• Continuous integration: GitLab CI, Git.
• Code quality: SonarQube, unit tests.
• Infrastructure and tools: Docker, Nexus.
• Project management: Jira, Confluence.
• Methodologies: Agile / Scrum.
• Team: 1 Tech Lead, 8 ReactJS developers, 3 Product Owners, 2 testers, and 2 UX/UI Designers
• Methodology: Agile / Scrum, 3-week sprints
• Technical Stack: ReactJS, Next.js, JavaScript, TypeScript, GitLab CI, SonarQube, Nexus, Docker, Jira, Confluence

Project details

• Start: 30/11/2026
• Duration: 3 mois renouvelable
• Remote: hybrid
• Location: Paris, Île-de-France, FR
• Rate: 50-65 EUR/h
• Languages: French