Fullstack .NET & Flutter Developer M/F

Who are we?

Joining NEXTON means joining a company where the spirit of a consulting firm, the creativity of a Factory, and the dynamics of an ESN converge! Thanks to our expertise, we support major accounts and pure players such as SNCF, Orange, and BNP Paribas in their digital evolution and innovation strategies.

Founded in 2011, NEXTON now brings together a team of more than 450 experts specialized in digital, design, agility, product, and development. Together, they create an ecosystem rich in knowledge and diverse skills.

NEXTON is recruiting a Fullstack .NET & Flutter Developer M/F, on a CDI (permanent contract), in Paris!

Your future work environment:

For one of our major clients in the business services and payment solutions sector, you will join a key tribe dedicated to the development of an international mobile application used daily by millions of users. Within an agile, multi-country, and multidisciplinary organization, you will contribute to the end-to-end development of backend and mobile features aimed at fostering engagement, usage, and retention. This role will allow you to evolve in a stimulating environment applying the "you build it, you run it" principle while combining software engineering and the use of advanced AI tools.

Your missions:

• Design, develop, test, and maintain robust, secure, and high-performance .NET backend APIs and services.
• Develop and evolve Flutter mobile features integrated into user journeys.
• Take full responsibility for complex features from end to end, from the design phase to production.
• Ensure global consistency between APIs, data models, and the user experience on the mobile application.
• Propose, defend, and implement technical architecture choices, business modeling, and product design in a Scrum environment.
• Guarantee a high level of code quality by applying Clean Code principles, Clean Architecture, pair programming, and performing automated tests.
• Address challenges of performance, scalability, security, and data protection across backend and mobile perimeters.
• Ensure the operation, stability, and performance monitoring of developed components while respecting the "you build it, you run it" approach.
• Integrate AI development agents into your daily workflows to automate certain tasks while remaining fully responsible for the final quality.

At least 8 years of experience in software development, with proven expertise in either .NET backend or Flutter mobile, as well as at least 1 to 2 years of production practice in the second area.

• Excellent mastery of Clean Architecture, Clean Code principles, automated testing, and code reviews.
• Solid skills in C#, REST APIs, microservices architectures, business modeling, databases (MongoDB, PostgreSQL) and/or Flutter, Dart, state management, and modular mobile architectures.
• Understanding of CI/CD, observability, and monitoring challenges for backend services and mobile applications.
• "Power user" level in the use of application AI tools and development agents.
• Autonomy, proactivity, team spirit, rigor, and fluent professional English to evolve in an international environment.

Why choose NEXTON?

We offer you benefits and opportunities to enrich your professional and personal experience throughout the year:

• Dynamic communities to support you in your journey.
• Meet Ups to develop your skills.
• Training to reinvent yourself and progress.
• Sporting and festive events to thrive.
• A sustainable mobility package to facilitate your daily life and encourage soft mobility.
• A latest-generation phone to stay connected.

Ready to join us? Let's meet!

NEXTON