Senior Fullstack Developer C#/.NET (m/f/d)

Sag Ag; Köln; Vor Ort; EUR 60.000 - 80.000; Vollzeit

Benefits dieser Stelle

Flexible working hours

Agile work environment

Continuous development budget

Zusammenfassung

Sag Ag in Köln is seeking a Senior Full-Stack Developer to lead the Webshop Team. You will own features and improvements across e-commerce platforms, ensuring a smooth experience for millions of users.

The ideal candidate has over 5 years of experience with C# / .NET and a strong command of ASP.NET Core and SQL. Join us for an agile work environment, flexible hours, and a team that values collaboration and innovation.

Be part of shaping the future of digital solutions!

Qualifikationen

• 5+ years of experience as a full-stack developer.
• Proactive, structured mindset with strong technical ownership.
• Experience in e‑commerce or marketplace environments is a plus.

Aufgaben

• Own and evolve features across the full stack of our e-commerce webshops.
• Build and improve customer-facing storefront experiences.
• Collaborate on software architecture and maintainability.

Kenntnisse

C# / .NET

ASP.NET Core

SQL

Microsoft Azure cloud services

React

Fluent English

Tools

MS SQL Server

PostgreSQL

Git

Jobbeschreibung

ABOUT US

SAG Digital is a subsidiary of Swiss Automotive Group AG (SAG), a leading company in the independent automotive aftermarket across Europe. With a strong presence in 12 countries, SAG generates annual sales exceeding 1.1 billion euros. At our offices in Cologne (GER), Cham (CH), Cluj, and Satu Mare (RO), we design, develop, and operate innovative e-commerce solutions, webshops, and apps for SAG companies. Our expertise spans cloud/DevOps, Agile software development, ERP, logistics, and IT security, enabling us to drive digital transformation in the automotive aftermarket.At SAG Digital, we're not just another company – we're a family of forward-thinkers, innovators, and passionate individuals who are dedicated to transforming the automotive aftermarket industry. Here, we're not just building careers; we're forging futures. Explore our world and discover why SAG Digital is the place for you.

WHAT YOU'LL DO

As a Senior Full-Stack Developer, you join our Webshop Team and take end-to-end ownership of features and improvements across our e-commerce platforms – from database and backend services to the user-facing experience. You ensure stability, performance, and a smooth shopping experience for millions of users, while continuously evolving a mature product landscape.

You go beyond implementation: you analyze and understand complex problems, challenge assumptions, and actively drive technical decisions in close collaboration with developers, architects, product, and business stakeholders.

• Own and evolve features across the full stack of our e-commerce webshops – backend, database, and frontend
• Build and improve customer-facing storefront experiences as well as internal tools supporting the webshop
• Optimize SQL queries and ensure high performance in data-intensive workloads
• Evolve database structures in a living, business-critical environment
• Collaborate on software architecture, maintainability, and system evolution to reduce technical complexity instead of adding to it
• Use Git (GitLab and/or GitHub) and contribute to modern CI/CD pipelines
• Work closely with product, developers and business stakeholders to identify real problems and create effective solutions

WHAT YOU BRING

• 5+ years of experience as a full-stack developer with C# / .NET, including solid hands‑on experience with .NET Framework
• Strong ASP.NET Core know‑how
• Solid SQL know‑how and experience with relational databases (e.g. MS SQL Server, PostgreSQL)
• Hands‑on experience with Microsoft Azure cloud services
• Proactive, structured mindset with strong technical ownership
• A mindset that balances pragmatism and quality in evolving, non‑greenfield environments
• Experience in e‑commerce or marketplace environments is a plus
• React know‑how is a plus
• Clear communication and the ability to work with both technical and non‑technical peers
• Fluent in English (working language in tech and cross‑team collaboration)

WHAT WE OFFER

• A key role in our Webshop Team, working on platforms with real business impact for millions of users
• Significant influence on architecture and technical direction
• High level of autonomy and pragmatic, outcome‑driven decision‑making
• Short decision‑making paths and direct communication
• A team that values collaboration, clarity, and continuous improvement
• Flexible working hours and remote options
• Agile work environment with clear Scrum processes
• Continuous development with a guaranteed annual learning budget
• Access to cutting‑edge technologies and tools
• A Regina Maria health subscription
• A 13th salary at the end of the year
• Regular team events like summer parties and monthly lunches
• A diverse and international team culture

Welcome to SAG Digital: Your Future Awaits!

Join us and be part of a dynamic team driving digital innovation in the automotive aftermarket. Shape the future of e-commerce with us – we look forward to meeting you!