We are seeking a Senior Backend Engineer (.NET) to join our client’s expanding engineering organization focused on a global payments platform. This hands-on position offers significant architectural influence, allowing you to design, build, and enhance a scalable, secure, and compliant platform that facilitates seamless payment experiences worldwide.
In this role, you will collaborate closely with multiple domain teams, including Wallets & Accounts, Payments, Client, Defend & Protect, and Frontend. You will contribute to a modern microservices architecture and help establish best practices for both the backend and the platform.
What You Will Be Doing
- Design, build, and evolve backend microservices and APIs using C# and modern .NET.
- Contribute to architectural decisions around microservices, scalability, resiliency, and security.
- Apply Domain-Driven Design (DDD) principles to define clear domain boundaries and maintainable systems.
- Translate business requirements, epics, and user stories into robust technical designs and implementation plans.
- Write clean, testable, production-grade code and meaningful unit tests.
- Participate actively in sprints, code reviews, and pair programming.
- Collaborate closely with Product Owners, DevOps, Platform, and QA teams.
- Ensure services meet performance, observability, and operational readiness standards.
- Uphold strict security and compliance requirements, including PCI DSS and GDPR.
Technical Environment
- Backend: C#, .NET Core / .NET 6+
- Architecture: Microservices, REST APIs, Domain-Driven Design
- Databases: SQL Server (performance optimization, complex queries)
- Cloud & Infrastructure: Azure, Kubernetes (AKS)
- Security: OWASP best practices, secure coding
- Ways of Working: Agile / Scrum, CI/CD, code reviews, shared service ownership
What We’re Looking For
Must-Have Experience
- Strong, hands-on experience with C# and modern .NET in production environments.
- Solid understanding of microservice architectures and distributed systems.
- Experience designing and consuming RESTful APIs.
- Very good knowledge of SQL Server, including query optimization.
- Understanding of secure coding practices and OWASP principles.
- Experience working in Agile/Scrum teams.
- Confidence contributing to code reviews with constructive feedback.
Strong Plus
- Experience applying Domain-Driven Design (DDD) in real systems.
- Hands-on exposure to Azure and Kubernetes in production.
- Background in fintech, payments, banking, or other regulated environments.
- Familiarity with observability, logging, monitoring, and service resiliency.
- Experience with messaging or event-driven architectures.
Why this role?
You’ll join a global payments technology company and work on a core backend platform used in real-world, high-scale financial systems.
The role is hands-on, with real ownership over backend services and the opportunity to contribute to architecture and technical decisions, while collaborating closely with product, DevOps, and platform teams.
What’s in it for you:
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Hybrid working model based in Sofia.
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Competitive compensation and a company bonus scheme.
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Strong benefits package, including additional annual leave, health insurance, wellbeing programs, and professional memberships.
If you are seeking a position where engineering quality, scalability, and security are paramount, this is an excellent next step. Feel free to send us your CV!
All applications will be treated as strictly confidential.
Only short-listed candidates will be contacted.
License for recruitment for Bulgaria: № 2399 / 15.11.2017.
License for administration and protection of personal data: № 432025 / 23.10.2017
