Senior Backend Developer (.NET / Azure)

S4D; Amsterdam; On-site; EUR 70,000 - 110,000; Full time

Job summary

S4D is seeking a Senior .NET Backend Developer to own backend services from architecture through deployment across our cloud platforms. You will craft clean C# code for modern .NET Core runtimes and design scalable microservices that power our SaaS offerings.

You will mentor junior engineers, promote TDD and clean code, and drive testability and performance. Familiarity with Azure Service Bus, MassTransit, RabbitMQ, and AI-assisted tooling is a plus.

Qualifications

• 5+ years of backend software engineering with C# and .NET Core.
• Experience mentoring junior/mid-level engineers and promoting best practices (TDD, clean code).
• End-to-end ownership of backend features from idea to production deployment.
• Strong understanding of microservices and event-driven messaging.
• Experience with Azure Cloud infrastructure and CI/CD practices.
• Testing mindset with unit/integration testing focus.

Responsibilities

• Own backend services across full lifecycle from architecture to deployment.
• Mentor and coach junior/mid-level developers, conduct code reviews.
• Define architectural patterns and design scalable microservices.
• Develop clean, modular C# code for modern .NET runtimes.
• Build asynchronous integrations using Azure Service Bus and MassTransit.
• Champion automated testing, CI, and performance profiling.
• Leverage AI coding tools to boost productivity.

Skills

C#

.NET Core

Mentorship

Event-driven

Azure

Tools

Azure Service Bus

MassTransit

RabbitMQ

Kafka

Kubernetes

Job description

About The Company

S4D is a Software as Service (SaaS) company that provides Quick Service Restaurants (QSRs) with the omnichannel operating system to run their business in the most effective and efficient way. In other words, we help restaurants to get more orders. Our team builds and services innovative products based on the newest technologies, consisting of a wide variety of functionalities and innovative modules while offering our employees flexible working conditions. Our key values are teamwork and ownership. S4D is part of the Deloitte Technology Fast 50 and Saas100 company (selected by MT/Sprout).

About The Role

We are looking for a Senior .NET Backend Developer who combines strong system design skills with a passion for engineering excellence. In this role, you will take end-to-end ownership of core backend services - driving solutions from initial architecture through deployment and production across our cloud platforms.

Beyond shipping high-quality code, you will play a key role in raising the engineering bar across the team. You’ll mentor mid-level and junior developers, establish best practices around testability and clean architecture, and foster a collaborative environment. We also encourage our engineers to utilize modern AI developer tools (like Cursor, Claude code) to accelerate daily workflows and problem-solving.

No unsolicited services from recruitment agencies.

Responsibilities

• End-to-End Ownership: Own backend services across their full lifecycle—from initial architectural design and technical scoping to coding, deployment, and operational health.
• Mentorship & Team Leadership: Coach and mentor junior and mid-level developers, conduct constructive code reviews, and help elevate engineering standards across the team.
• System Design & Architecture: Help define architectural patterns, design scalable microservices, and ensure our event-driven integration flows are resilient and decoupled.
• Hands-on Service Development: Write clean, modular, and maintainable C# code targeting modern .NET Core runtimes.
• Messaging & Workflows: Build robust asynchronous integrations using Azure Service Bus and MassTransit.
• Quality & Performance: Champion automated unit testing, continuous integration, and proactive performance profiling.
• AI-Assisted Engineering: Utilize AI coding tools to boost daily productivity and streamline system troubleshooting.

What You Bring (Mandatory)

• 5+ years of hands-on backend software engineering experience with C# and .NET Core.
• Mentorship Experience: A proven track record of guiding junior/mid-level engineers, sharing knowledge, and fostering best practices (TDD, clean code, peer reviews).
• End-to-End Feature Ownership: Demonstrated experience designing and delivering backend features from initial idea to production deployment.
• Event-Driven Mastery: Solid understanding of microservices patterns and event-driven messaging (Azure Service Bus, MassTransit, RabbitMQ, Kafka, etc.).
• Azure Cloud Experience: Practical experience working with core Microsoft Azure infrastructure and cloud components.
• Testing Mindset: Deep appreciation for testable architecture and unit testing best practices.

Nice-to-Haves

• Experience with Kubernetes and container orchestration.
• Knowledge of SQL Server relational database design and optimization.
• Familiarity with modern CI/CD pipelines and DevOps workflows (Azure DevOps / GitHub Actions).
• Hands-on experience with MassTransit specifically.
• Experience with legacy system migration (.NET Framework to modern .NET).
• Familiarity with developer AI tooling (e.g., Cursor, Claude code).