Full Stack Developer C# / .NET

Project overview

Our client in the Banking and Finance sector is looking for a Full Stack C# / .NET Developer H/F

Mission Description:

Context

A medium-sized company with a human-sized IT department wishes to strengthen its internal team, which currently outsources part of its projects. Its application portfolio is historically based on WinDev, WebDev, and HFSQL. Following a change in the publisher's license model, a progressive migration to a Microsoft environment (C# / .NET) and PostgreSQL is underway, with a planned exit from PC Soft in 2027.

The applications are mainly business tools and transactional applications. Some are used on rugged PDAs and tablets by field teams, particularly for barcode scanning, process tracking, and data entry. The infrastructure, hosted entirely on-premise on Windows Server 2022 and 2025, is not affected by the migration.

Mission

As part of a long-term freelance mission, with a prospect of permanent employment (CDI) at its conclusion, the developer will primarily contribute to the development of new business applications in C# / .NET and the progressive modernization of the application portfolio. The mission begins with a multi-month skills transfer on the existing PC Soft applications, which will need to be supported during the migration.

Main Responsibilities

Technical Environment

Profile Sought

Experience

Technical Skills

Personal Skills

Terms

Mandatory Skills / Qualities:

Application development in C# / .NET, SQL proficiency, Full stack development and interface redesign, Data migration, Autonomy and versatility in a small team

• Develop new versions of business applications in C# / .NET.
• Contribute to the migration of data from HFSQL to PostgreSQL: modeling, queries, and data recovery.
• Redesign application interfaces for workstations, rugged tablets, PDAs, and web. The front-end technology is yet to be chosen and must integrate well with C#; screens should be simple, robust, and practical for field teams.
• Learn the existing WinDev and WebDev applications through skills transfer, then provide support during the migration.
• Contribute to certain reporting needs under Power BI.
• Provide support for system administration and digital workplace needs as required.
• Development: C#, .NET, WinDev, WebDev
• Databases: PostgreSQL, HFSQL, SQL
• Reporting: Power BI
• System Environment: Windows Server 2022 and 2025, on-premise infrastructure
• Interfaces and Usage: desktop, web, and mobile applications on rugged PDAs and tablets; target front-end technology to be chosen
• Approximately 5 years of application development experience.
• Full-stack development experience is appreciated, especially in front-end development.
• Experience with mobile applications or tablets for field teams is appreciated.
• Data migration experience is appreciated.
• Very good command of C# / .NET and SQL.
• Openness to learning PC Soft, an existing end-of-life technology.
• Knowledge of PostgreSQL, WinDev / WebDev, Power BI, and Windows Server system administration is appreciated.
• UX / UI expertise, DevOps culture, or Agile/certified profile are not required. Deployments remain simple and steering tools are lightweight.
• Versatile profile, interested in various back-end, front-end, database, and system administration topics rather than a single specialization.
• Autonomy, resourcefulness, and enjoyment of working in a small team.
• Long-term freelance mission, with a prospect of permanent employment (CDI) at its conclusion.
• Multi-month skills transfer on existing applications at the start.

Nice to have

Full stack and front-end development experience; knowledge of PostgreSQL and data migration experience; experience with mobile applications or tablets for field teams; basic knowledge of Windows Server system administration and Power BI; knowledge of WinDev / WebDev.

Information regarding teleworking:

Yes — 1 day/week

Project details

• Start: flexible
• Remote: hybrid
• Location: Paris, France, FR
• Rate: 53-53 EUR/h
• Languages: French