Senior Software Engineer – Java (f/m/x)

At Seven Senders, we connect people and markets, making international shipping simple. We are Europe’s leading platform for cross-border parcel delivery, supporting e-commerce companies in scaling internationally and reaching millions of consumers across borders. By combining cutting-edge technology with strong local carrier networks, we ensure parcels move efficiently from warehouse to doorstep — whether speed or cost efficiency is the priority. Founded in Berlin in 2015, Seven Senders has grown into a team of 200+ logistics and tech experts. Today, we proudly work with clients such as Flaconi, Shop Apotheke, and Tamaris, shaping the future of European delivery together. Do you want to build the systems that physically move parcels across Europe, generate shipping labels at scale, and turn a constant stream of carrier scans into real-time tracking for millions of shipments? We are looking for a Senior Software Engineer to join our Carrier Integration Team. You will design, build, and operate the backend services that integrate Seven Senders with Europe's carriers end-to-end; from label generation, routing, and returns to ingesting and normalizing parcel tracking events from dozens of carrier APIs, EDI feeds, and webhooks. You will own the full lifecycle, from architecture to production, on a modern, event-driven JVM stack built around Domain-Driven Design. Our core tech stack includes Java 21 (moving to 25), Spring Boot 3/4, MongoDB, MySQL, Kafka (AWS MSK), Vue, AWS, Docker, and Kubernetes. Your main responsibilities: Design, develop, and operate backend microservices using Java and Spring Boot, following Domain-Driven Design and clean architecture principles. Build event-driven pipelines using Kafka and SQS to ingest, normalise, and distribute high-volume carrier-tracking events. Integrate new carriers across REST, SOAP, EDI, and SFTP, designing resilient clients for third-party APIs. Design efficient, scalable data models in MongoDB and MySQL. Deploy and operate containerised services on Kubernetes (AWS, Datadog, Prometheus), writing well-tested, contract-first code and actively contributing to design discussions, code reviews, and agile ceremonies. This is what you need to succeed: 5+ years of backend development experience with strong proficiency in Java and the Spring Boot / Spring ecosystem. Solid experience with microservices and event-driven architectures (Kafka, SQS, or equivalent), and contract-first API development with OpenAPI. Hands-on knowledge of both NoSQL (MongoDB) and relational (MySQL) databases, including data modelling and performance tuning. Strong grasp of Domain-Driven Design and software architecture, with proven experience integrating third-party APIs and designing for resilience against unreliable upstreams. Production experience with Docker, Kubernetes, and cloud-native AWS environments; familiarity with GraalVM native images and Vue + TypeScript is a plus. What we offer: Flexible & Hybrid Work: Our office is at Alexanderplatz; we have a hybrid working model with flexible remote-office set-up and working hours. And if you wish, you can work from almost anywhere for up to 2 months per year. Benefits: We offer company lunches twice per month, a corporate benefits platform, and German language courses. Mission Zero: Climate-neutral and long-term impact. With our green initiatives, we are reaching climate neutrality for ourselves, and hopefully, we're inspiring the entire logistics sector to join us to create a sustainable future. Vibrant Culture & Community: We embody collaboration, open doors, and no-fuss results focus, and we are successful with our data-driven and efficient working approach. We like to celebrate and come together, and we strive for a workplace buzzing with energy and camaraderie, highlighted by regular team events, and company-wide celebrations. Inclusive Environment: We value diversity and welcome all applicants regardless of ethnicity, religion, national origin, sexual orientation, gender identity, age, or disability. If you meet the above qualifications and are excited about the opportunity to join our team, we encourage you to submit your application today. Please scroll down to submit your English CV. We look forward to hearing from you!