Staff Backend Engineer – Fulfillment & Logistics (f/m/d)

Your mission

JTL is one of the leading providers of e-commerce software in the German-speaking region – with around 450 employees across the corporate group and more than 50,000 customers from a wide range of industries. We develop scalable, flexible solutions for the online retail of the future – from ERP systems to shop and marketplace integrations.

You will become part of the team behind our Fulfillment Network – the backend that keeps orders, inventory and logistics running for thousands of merchants. We care about systems that run reliably and get better with every release, and we keep ownership close: whoever builds a service also operates it. You’ll fit in here if you enjoy backend problems that carry real operational weight.

This is a backend-first role – you see yourself primarily as a backend developer, and the core of the work lies in the .NET / MongoDB space. You develop the REST API behind our Fulfillment Network (FFN) and Trade Network (TDN), products used every day by thousands of customers, and you own the integration points where backend services and the JTL-Wawi client have to work together seamlessly.
You think in systems and data flows rather than isolated tickets, switch effortlessly between technologies, and thrive in a fast-moving, startup-like environment. The principle here is simple: you build it, you run it. You don’t own the underlying hardware, but you’re responsible for your application’s operational readiness from start to finish – when issues arise, you fix them the same business day. Stability and availability matter to you as much as shipping new features, and you take pride in making the product faster and more reliable with every iteration.

Your responsibilities

• You continue to develop our FFN/TDN REST API and own backend features from start to finish – from design through to production
• You build the integration with JTL-Wawi, especially where backend services and client-side behaviour have to work together seamlessly
• You support complex business and synchronization scenarios and take care of production incidents and customer-reported issues
• You operate and deploy the API through our pipelines – including performance optimization, observability and operational reliability
• You’re responsible for your application’s operational readiness from start to finish: you build it, you run it – and you fix issues the same business day

Your profile

• C#, modern .NET (.NET 8+) and ASP.NET Core are your primary stack – with solid, hands-on experience building and operating backend services in production
• You have built and maintained complex backend systems with a focus on robustness, maintainability and scalability – using modern .NET patterns (async/await, dependency injection, Clean Architecture), CQRS and Domain-Driven Design (DDD)
• You know MongoDB well (data modelling, performance optimization, large data volumes) and have strong SQL skills, including writing and optimizing complex queries
• You design and consume REST APIs on both sides (Core & Connect) and can identify and resolve bottlenecks across APIs, database access and backend workflows
• You have hands-on observability experience with Prometheus and Grafana – metrics, dashboards, alerting, production analysis – and solve customer-reported issues pragmatically and reliably
• You have worked with AI-assisted development and agentic, automation-oriented engineering where it creates real value
• Good German communication skills

Nice to have

• Background in ERP or e-commerce
• Domain knowledge in logistics or fulfillment
• PHP — hands-on production experience, ideally in the Laravel ecosystem
• MariaDB / MySQL — data modelling and query optimization
• Livewire / Tailwind — no deep expertise required, but the ability to work independently
• WPF — hands-on experience working on existing desktop UI applications
• DevExpress — experience with component-based desktop UI development

Why us?

• Remote-first within Germany, with the option to work remotely from eligible countries for up to 180 days per year
• Meal allowance of up to €115 net per month
• Subsidy for an ergonomic home-office workplace
• Regular team events, company-wide gatherings as well as summer and Christmas parties to stay connected as a remote-first company
• EGYM Wellpass and JobRad subsidy
• Additional financial benefits including capital-forming benefits (vermögenswirksame Leistungen) and a company pension scheme