Expert/Lead C#/.NET Developer

About the Position

We are seeking an Expert/Lead C#/.NET Developer with 8+ years of experience in server-side .NET development to join our team in Warsaw, Poland. This role focuses on distributed systems and platform engineering.

Responsibilities

• Design and implement backend features across Kepler's.NET/Windows services, MassTransit sagas, and infrastructure layers.
• Take technical ownership of assigned Kepler subsystems: understand their design rationale, identify improvement opportunities, and drive implementation.
• Possibly lead and mentor EU-based developers: code review, pairing, unblocking, and growing their capability over time.
• Collaborate asynchronously with the NYC-based team lead and wider client's team. Reliable written communication across a 5-6 hour time difference is essential.
• Contribute to design discussions, technical documentation, and architecture decisions as a full peer - not a ticket-taker.
• Maintain and improve observability, deployment practices, and platform reliability for the areas they own.

Requirements

• 8+ years of commercial software engineering experience, the majority in server-side .NET development in production environments.
• Hands-on experience with RabbitMQ or a comparable broker (Kafka, Azure Service Bus). Understands exchanges/queues/bindings or equivalent topology concepts - not just 'I have used a queue'.
• Demonstrable distributed systems depth: has built things that had to be reliable, had to handle message ordering and deduplication, and had consequences when they were wrong.
• Experience with saga-style or long-running workflow patterns. Has implemented stateful multi-step processing where steps arrive out of order, from multiple sources, or with long windows.
• Writes meaningful tests as part of normal development - not as an afterthought. Understands the difference between unit, integration, and contract tests and applies them appropriately.
• Comfortable deploying and running.NET services on Windows Server. Does not require a Linux/container environment to be productive.
• Has led or mentored engineers in some capacity - formal or informal. Can explain their approach to code review, feedback, and developing junior engineers.
• Reads and writes clear technical prose. Can produce a design document, a runbook entry, or a detailed pull request description without prompting.
• Asks the right questions about a new codebase rather than immediately reaching for rewrites. Respects existing design decisions until they understand them.
• Self-directed and reliable in a remote, asynchronous context. Has done this before and can point to how they managed it.

Nice to Have

• Experience with HashiCorp Nomad or a comparable orchestrator (understanding of job scheduling, placement, health checks).
• Familiarity with Consul or a comparable service discovery and KV store.
• Experience with MassTransit specifically - its publish topology, saga persistence, outbox pattern, or transport configuration.
• MongoDB experience, particularly as a document store for structured state (not necessarily as a primary database).
• Exposure to YARP or other programmatic reverse proxy / API gateway frameworks.
• Experience with Splunk or a comparable log aggregation and search platform.
• Familiarity with OpenTelemetry and distributed tracing concepts.
• Experience operating services across multiple environments with a promotion pipeline (dev → staging → production or equivalent).
• Experience with Next.js or TypeScript.
• Familiarity with Jenkins or GitHub Actions CI pipelines.
• Exposure to JFrog Artifactory or similar artifact management.
• Any financial systems context - even adjacent (payments, order management, data pipelines) - as background, not a requirement.

We Offer

• Relocation options
• Experience in an international environment
• Cross-cultural experience
• Feedback culture
• Regular appraisals
• Annual holiday - 20 or 26 days (depending on seniority)
• Occasional leave - 1 or 2 days (depending on circumstances)
• Child care leave - 2 days or 16 hours per year
• Absence due to force majeure - 2 days or 16 hours per year
• Maternity Leave - 20 weeks
• Parental Leave - 41 weeks
• Paternity Leave - 14 days
• Expert-led tech courses
• Internal instructor-led soft skills courses
• Comprehensive in-house self-learning resources
• Access to external self-learning libraries like ProQuest eBook and Udemy for Business
• Cloud Programs: MS Cloud Academy, AWS Partner Academy, Google Cloud Academy
• Custom Learning Programs: upskilling, reskilling, technical mentorship
• Leadership Programs for Managers
• Multisport card
• Possibility to order Multisport card at the corporate rate for family members
• LuxGood Program: wellbeing seminars, contests, relaxation sessions, yoga sessions, etc.
• One Team Program: Buddy for each New Joiner; seminars, meeting and workplace space to support integration with local community and culture; “Hire me” workshops for partners
• Preferential banking offer
• Preferential car leasing offer
• Cafeteria program discounts for shops, cinema tickets, holiday offers
• Luxoft Social Benefit Fund: sport and recreation benefits, the possibility to receive financial support
• Private Healthcare Insurance with unlimited access to specialists
• Full dental support
• Travel Insurance
• Possibility to add private healthcare coverage for family members at the corporate rate
• Life insurance at the corporate rate for employees and family members, including payment of the basic package for the employee by the employer
• Reimbursement for corrective glasses
• Many fun social activities organized by the Luxoft team offline in your city
• Online entertainment events for the whole company and local team events
• A workplace where you’re treated with respect within a multicultural team
• Rotation between projects and accounts
• New career opportunities

About the Company

Luxoft is a global IT services company that specializes in software development, digital transformation, and consulting services. Our mission is to empower businesses to achieve their digital ambitions through innovative technology solutions.

Apply now to join our team in Warsaw, Poland, and contribute to our cutting-edge projects!