Expert / Lead C#/.NET Developer

Description

Client's application is a modern distributed application platform built on.NET and Windows, structured as a monorepo and operated across nine environments. It integrates a 30-year-old core financial system with modern consumers by providing event-driven processing, saga orchestration, API gateway, and observability infrastructure. The platform is maintained by a small, senior team. Engineers here own the full stack from architecture through production operations. The problems the candidate will work on are fundamentally distributed systems and platform engineering problems. A representative sample of current and near-term workstreams: Blue/green deployment topology: zero-downtime service cutover using RabbitMQ exchange binding management, slot affinity middleware, and a topology reconciler. Stateless, eventually consistent, and operationally simple by design. Release and deployment pipeline: GitOps-style release management with strongly-typed release candidates, deployment profiles, and CalVer artifact versioning across a nine-environment promotion pipeline. Structured observability: Splunk Cloud log aggregation, structured log properties, distributed tracing via MassTransit/OpenTelemetry, and RabbitMQ queue metrics. Regression framework: an event-driven, eventually consistent, embarrassingly parallel regression system that compares PROD and UAT output streams per correlation ID using developer-written reconcilers. Saga-driven trade processing: multi-stream correlation, idempotent booking, ordered state machine transitions, and durable state across service restarts — all via MassTransit and MongoDB.

What we offer

• Global Relocation - (Relocation options; Experience in an international environment; Cross-cultural experience)

• Recognition and Evaluation - (Feedback culture; Regular appraisals)

• Time Off - (Annual holiday - 20 or 26 days. The duration of the leave depends on the overall seniority; Occasional leave - 1 or 2 days/ depending on the 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)

• Luxoft Training Center - (Expert-led tech courses covering basic to advanced topics; Internal instructor-led soft skills courses; Comprehensive in-house self-learning resources for both soft and hard skills; 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)

• Well-being and Work-life Balance - (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)

• Health Care - (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)

• Company Events and Friendly Environment - (Many fun social activities organized by the Luxoft team offline in your city; Online entertainment events for whole company and local team events; A workplace where you’re treated with respect within a multicultural team)

• Internal Mobility - (Rotation between projects and accounts; New career opportunities)

• Self-Learning Library

• CSR Projects

Other

• Languages: English: C1 Advanced

• Seniority: Lead

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.

• Strongly Preferred

• Candidates who bring several of these will be significantly stronger fits. None are individually disqualifying to be missing.

• 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.

Responsibilities

• The successful candidate will join client's team as a senior engineer working remotely from within the EU time zone. They will work autonomously on large, critical subsystems of the platform, possibly lead a small local team (also in the EU), and serve as the primary engineering contact for that team's day-to-day execution. They are not a delivery manager — they are a hands-on engineer who also leads.

• Day-to-Day 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