Senior C# .net Fullstack-developer

40 hours
Meppel (Near Zwolle)

At GMU, we develop groundbreaking, scalable SaaS solutions that make a real difference for eCommerce entrepreneurs. Our mission? To help webshops worldwide reliably and predictably optimize their profitability by fully automating Google Shopping, data feeds, and campaigns through our own proprietary platform and app.

What you’ll be doing

At GMU, you’ll work on two core pillars of our technology:

Business Analytics App

Free revolutionary business intelligence for every online entrepreneur.
  • Easily generated business analyses and clear insights for profitable growth
  • Continuous clarity on your ROI progress, empowering you to make informed decisions with confidence
  • Instantly monitor your Return on Ad Spend (ROAS), revenue, investments, visitor traffic, and conversion rates
  • Access comprehensive insights anytime, anywhere, to stay ahead of the competition
  • In-depth customer analysis: track both new and existing customers with detailed metrics

Martech Automation Software – Help build the engine behind 900% ROI

To enable these exceptional results, we are developing our own Marketing Technology Software (Martech Automation).

A Decision Hierarchy (Decision Engine):
Dynamic decision-making rules are applied here. They automatically determine where and how budgets are allocated for maximum growth.

Feed Automation Systems:
Product feeds, ad copy, and targeting are automatically optimized based on real-time data.

GMU = Best Place to Work 🎉

About You

  • Minimum of 10 years of professional experience in C# .NET backend development combined with React frontend development (or other modern JS frameworks)

  • You have worked on complex, modular systems, you think in patterns and scalable architecture, not in temporary solutions.

  • You will help shape the backbone of GMU’s proprietary software and client performance tools.

  • You have experience designing and developing scalable applications using C# .NET and React, built on a microservices architecture.

  • You design fast and intuitive user interfaces for internal teams and clients, speed is key.

  • You build scalable and efficient software using event-driven architecture and microservices.

  • You are hands-on with CI/CD pipelines, feature flags, and take full ownership of deployments.

  • You are experienced in cloud-native development, specifically on Microsoft Azure.

  • You work closely with our AI, R&D, and marketing performance teams.

  • You understand the balance between developer experience and delivering real business value.

  • You take full responsibility for your projects, from initial concept to beta release, refactoring, and long-term maintenance.

Bonus Points

  • Experience with Google APIs, server-side tracking, or e-commerce platforms

  • Affinity with performance marketing or building tools for marketing teams

The Tech Stack you'll work with

  • Backend: C# (.NET Core / .NET 6+), Azure Functions, Microservices architecture

  • Frontend: React (Web and React Native for Mobile)

  • Databases & Caching: Azure SQL Database, Redis, Cosmos DB, Elastic Search

  • DevOps & Deployment: Azure DevOps, GitHub Actions, Docker, CI/CD Pipelines, Feature Flags

  • Cloud: Microsoft Azure (focus on Microservices, Service Bus, Event Grid, Azure Functions)

  • Other: Webhooks, REST APIs, Cron jobs (Azure Timer Functions), AI API Integrations (Azure Cognitive Services, OpenAI)

AI, R&D & Innovation

  • Leverage AI to accelerate learning and development

  • Active experience with AI APIs and generative AI

  • Use AI tools to enhance scalability and efficiency

  • Dedicate approximately 20% of your time to R&D and cutting-edge technologies

  • Actively contribute to our shared innovation culture

  • Collaborate closely with international e-commerce entrepreneurs and industry partners

  • Work on joint innovation projects with partners across the tech industry

Ownership, Creativity & Freedom

  • Full ownership over your projects from start to finish

  • Maximum freedom to create innovative and scalable solutions

  • Work in a culture that actively encourages innovation and creative contributions

Extra Bonus Points

  • Experience integrating AI into your development workflows

  • Experience accelerating your own development speed using AI

  • Familiarity with Large Language Models (LLMs)

  • Experience with Machine Learning technologies

Personal growth = GMU

🏆 Why you’ll love working with us

💎 We work exclusively with senior developers and marketers
🔝 Top 10 FD Gazelle: One of the fastest-growing companies in the Netherlands
💰 An average client ROI of 900% (happy clients!)
❤️ Our clients rate us 9.6/10 and love working with us
🚀 21 years of perfecting our technology, and we’re just getting started!

💻 Work with the best hardware: you’ll get the fastest laptop and a 49” curved cockpit screen, allowing you to code across 5 screens simultaneously. Want to work with an absolutely epic setup? You can with us!

📚 Opportunities for training, new challenges, and career growth into leadership positions

💰 An exceptional, competitive salary matched to your experience

🎯 Ready for the ultimate challenge?


Apply Now  and show us why you are the high performer we’re looking for! 🚀

💡 Our Culture? We don’t call ourselves “staff”, we are a family.

🍽️ Luxury team dinners every 12 weeks

🎮 Game Night every Tuesday

🚀 Quarterly outings and team activities

🏡 Hybrid working? Working from home occasionally is fine, but team bonding and knowledge sharing are key; that’s why we’re usually together at our office in Meppel.

✈️ Freedom to temporarily work from abroad (for example, workcation)

🌎 International collaboration with e-commerce entrepreneurs and tech partners

🧠 20% R&D time, continuous innovation and diving into the latest technologies

🤖 AI as a growth accelerator: We leverage AI to learn faster and develop proofs of concept even more quickly.

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