N

NEXTON

Builds digital projects for large French firms

Fullstack Developer .NET & Flutter

Full-TimePosted on 10/15/2026
No salary listed
Senior, Expert
Île-de-France, France
In Person
Software EngineeringFull-Stack Engineering

About the job

Requirements
  • At least 8 years of software development experience, with strong expertise in either .NET backend or Flutter mobile development and 1–2 years of production experience in the other area.
  • Strong command of Clean Architecture, Clean Code, automated testing, and code reviews.
  • Strong skills in C#, REST APIs, microservice architectures, business modeling, and databases such as MongoDB and PostgreSQL, and/or Flutter, Dart, state management, and modular mobile architectures.
  • Understanding of CI/CD, observability, and monitoring for backend services and mobile applications.
  • Power-user proficiency with application AI tools and development agents.
  • Professional fluency in English for work in an international environment.
Responsibilities
  • Design, develop, test, and maintain robust, secure, and performant .NET APIs and backend services.
  • Develop and evolve Flutter mobile features integrated into user journeys.
  • Take end-to-end ownership of complex features, from design through production release.
  • Ensure consistency between APIs, data models, and the mobile application's user experience.
  • Propose, advocate for, and implement technical architecture, business modeling, and product design decisions in a Scrum environment.
  • Maintain high code quality using Clean Code, Clean Architecture, pair programming, and automated testing.
  • Address performance, scalability, security, and data-protection needs across backend and mobile areas.
  • Operate, stabilize, and monitor the performance of developed components according to the “you build it, you run it” approach.
  • Integrate development AI agents into daily workflows to automate tasks while remaining accountable for final quality.

About the company

NEXTON plans and builds digital projects for large French companies and online businesses, combining digital strategy with software development and marketing. Its teams cover product management, user-experience design, agile delivery and data work, and build websites, mobile applications and customer communications. Clients pay for specialist consultants assigned to their teams or for projects delivered by NEXTON's own agency. The agency combines designers, developers and marketing specialists to handle projects from planning and interface design through development and delivery. Founded in Paris in 2011, NEXTON is headquartered there at 5-7 rue Saint-Fiacre and operates across France.

Company Size

N/A

Company Stage

N/A

Total Funding

N/A

Headquarters

Paris, France

Founded

2011

Get referred to NEXTON

See people who can refer or advise you

Simplify Jobs

Simplify's Take

What believers are saying

  • NEXTON recruits entirely on permanent employment contracts, providing a salaried path into client assignments.
  • NEXTON consultants joined client Veolia at Google's enterprise-AI event in March 2026, studying tools alongside customer teams.
  • NEXTON's client portfolio spans rail, telecom and insurance through SNCF, Orange and AXA.

What critics are saying

  • NEXTON's Montpellier Java role pairs new banking features with incident analysis and corrective maintenance, per October 2026 posting.
  • French demand exposure: Numeum reported 1.8% contraction for 2025 IT services in December 2025; NEXTON's six offices are French.
  • NEXTON's Paris customer marketing lead handles mobile campaigns and supervises an apprentice, per its October 2026 posting.

What makes NEXTON unique

  • NEXTON runs an in-house digital factory in rural Saint-Augustin, extending project delivery beyond metropolitan offices.
  • Figma lists NEXTON as a service partner for design-system implementation, migration and team training.
  • NEXTON's seven employee-run communities connect mentoring, software, design, AI/data, sustainability, agile product work and sport.

Help us improve and share your feedback! Did you find this helpful?

Benefits

  • Commuter Benefits
  • Professional Development Budget