Senior Software Engineer (.NET/C#) - Logistics team

We are part of Allegro and we are specialists in providing advanced IT systems for logistics management. Massive Scale: Design and build high-availability systems used by tens of thousands of users. This is high-performance engineering in practice. Modern Tech Stack: Work with a world-class environment using C#, . NET Core, ASP. NET, REST, PostgreSQL, Azure, Docker, Kubernetes, EntityFramework, and Redis. True Ownership & Autonomy: We live by a 'you build it, you run it' philosophy. You'll join an autonomous team with full ownership of the services you create, from design to deployment. Complex Challenges: You will tackle complex backend problems, using technology to solve real-world business challenges. Join the team building the technological foundation of Allegro One logistics! Our systems support the end-to-end parcel flow - from pickup through sorting, depots, and last-mile delivery. Processing millions of logistics events daily, our backend services directly impact stability and efficiency for thousands of couriers, warehouse workers, and drivers. You will have a chance to build and refine the high-performance infrastructure powering our logistics network. We prioritize high reliability, modern engineering practices, and a supportive team culture. This role offers an excellent opportunity to actively shape our backend architecture while solving high-scale challenges. Important things for you: Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 10:00 a.m. We also have 30 days of occasional remote work. The salary range for this position depending on the skill set is as follows (contract of employment, tax-deductible cost):PLN 18 850 - 25 900Annual bonus based on your annual performance and company results. Long term discretionary incentive plan based on Allegro.eu shares (restricted stock units). Our team is based in Warsaw. We are looking for people who have: Core Technical Stack & Architecture: Extensive experience architecting high-throughput, low-latency backend systems using C# and . NET Core / ASP. NET Core; mastery of resilient RESTful APIs, modular monoliths, and microservices; deep expertise in relational database optimization using PostgreSQL and Entity Framework Core under high-concurrency workloads; pragmatic experience with legacy protocols (SOAP/WCF). Infrastructure & Distributed Systems: Hands-on production experience in cloud-native environments using Docker, Kubernetes, and CI/CD; strong background in event-driven architectures and distributed messaging via Azure Service Bus or Kafka; solid grasp of caching and optimization techniques to ensure high availability and eventual consistency. Mobile & Platform Integration: Understanding of backend considerations for mobile integration, including payload optimization, offline synchronization, push notification architectures, and API versioning. Leadership & Delivery: Proven technical leadership in mentoring engineers, driving code quality, and leading architectural reviews; full ownership across the SDLC from design to delivery; fluent in English (at least B2). What’s in it for you: Well-located offices (with e.g. fully equipped kitchens, bicycle parking, terraces full of greenery) and excellent work tools (e.g., raised desks, ergonomic chairs, interactive conference rooms). A Dell Laptop (Windows) and all the necessary accessories. A wide selection of fringe benefits in a cafeteria plan - you choose what you like (e.g., medical, sports or lunch packages, insurance, purchase vouchers). English classes that we pay for related to the specific nature of your job. A training budget, inter-team tourism (see more here), hackathons, and an internal learning platform where you will find multiple trainings. An additional day off for volunteering, which you can use alone, with a team, or with a larger group of people connected by a common goal. Social events for Allegro people - Spin Kilometers, Family Day, Fat Thursday, Advent of Code, and many other occasions we enjoy. And that's just the beginning! You can read more about the benefits here.#goodtobehere means that: You will join a team you can count on - we work with top-class specialists who have knowledge- and experience-sharing in their DNA. You will love our level of autonomy in team organization, the space for continuous development, and the opportunity to try new things. You get to choose which technology solves the problem and you are responsible for what you create. You will value our Developer Experience and the full platform of tools and technologies that make creating software easier. We rely on an internal ecosystem based on self-service and widely used tools such as Kubernetes, Docker, Consul, GitHub, and GitHub Actions. Thanks to this, you can contribute to Allegro from your very first days on the job. You will be equipped with modern AI tools to automate repetitive tasks, allowing you to focus on developing new services and refining existing ones (also leveraging AI support). You will create solutions that will be used (and loved!) by your friends, family and millions of our customers. You will meet the Allegro Scale, which starts with over 1000 microservices, an open-source data bus (Hermes) with 300K+ rps, a Service Mesh with 1M+ rps, tens of petabytes of data, and production-used machine learning. You will become part of Allegro Tech - We speak at industry conferences, cooperate with tech communities, run our own blog (it's been over 10 years!), record podcasts, lead guilds, and we organize our own internal conference - the Allegro Tech Meeting. We create solutions we love (and can) to talk about! Send us your CV and… see you at Allegro!