Senior .NET Developer - Fintech

Senior .NET Developer – Fintech
Location: Belgrade, Serbia  |  Employment Type: Full-time | Hybrid

About Us

We are a fast-growing company delivering operational and technology support for financial services providers. We build real, production-grade systems: a highly available, regulated, multi-tenant platform that moves money, data, and trust — wallets and ledgers, IBAN payments, card flows, crypto custody and exchange, compliance and transaction monitoring.

As our platform grows in transactional volume, regulatory demands, and third-party integrations, we need engineers who can turn these challenges into working, reliable solutions.

What You’ll Do

• Design, build, and evolve a production-grade .NET 10 modular monolith (ASP.NET Core Minimal APIs, CQRS with command/query handlers, module boundaries, shared kernel) powering payments, digital banking, and crypto flows for multiple tenants.
• Build event-driven flows with Wolverine and RabbitMQ: integration events, durable messaging, idempotent handlers, retries and dead-letter recovery.
• Develop and harden integrations with banking, payments, KYC, and crypto providers: REST APIs, OAuth, HMAC-signed webhooks, polling and reconciliation backstops that keep the ledger and the bank in sync.
• Work with EF Core 10 on SQL Server: schema design and migrations, efficient projections, indexing and query tuning, strict no-N+1 discipline on money-critical paths.
• Contribute to our Angular 19 front-ends (back-office and customer portals): services, interceptors, guards, RxJS/Signals, i18n.
• Own your modules end-to-end: development, xUnit testing, deployment via GitHub Actions to Azure, and production monitoring (Serilog, OpenTelemetry, Log Analytics).
• Operate production: diagnose incidents across application logs, database, and provider logs; reconcile money movements down to the last cent.
• Collaborate closely with architects, DevOps, product, and compliance (AML/sanction screening, transaction monitoring, risk rules, 2FA/SCA).
• Make and document technical decisions with incomplete information, balancing risk, quality, and delivery.

Tech Must-Haves

You should be hands-on and battle-tested with:

• 8+ years of professional .NET / C#, including correct async/await usage and CancellationToken discipline, solid understanding of memory, threading, and performance, and the ability to profile and diagnose production issues.
• ASP.NET Core (Minimal APIs preferred): dependency injection, middleware, authentication/authorization, API versioning.
• EF Core and SQL Server / T-SQL: migrations, query design, performance tuning, and indexing on high-volume transactional data.
• Architecture: modular monolith or well-structured service architectures, CQRS, domain events, clean module boundaries, backward-compatible change.
• Messaging: RabbitMQ (or similar) with Wolverine, MassTransit, or NServiceBus — event-driven design, idempotency, outbox/durable delivery, dead-letter handling.
• Real Azure experience: App Services, Azure SQL, Key Vault, Application Gateway/WAF, Log Analytics/Application Insights; CI/CD with GitHub Actions or Azure DevOps.
• External integrations and APIs, including third-party and fintech service providers: webhooks with signature verification, OAuth flows, resilience patterns (Polly), reconciliation.
• Angular (v15+), TypeScript, and RxJS, with practical production experience.
• Testing: xUnit (or similar), mocking, integration tests against real endpoints; refactoring legacy code safely.
• Security mindset: secrets management, input validation, secure auth flows (2FA/OTP, session enforcement), never exposing internals.

Nice to Have

• Payments domain knowledge: SEPA, UK Faster Payments, SWIFT, virtual IBANs, safeguarding/reconciliation.
• Crypto: custody platforms (e.g. Fireblocks), liquidity/OTC providers, on-chain transfer flows.
• KYC/AML tooling (e.g. SumSub, sanction screening providers) and transaction-monitoring logic.
• Multi-tenant SaaS architectures.

What We Value in This Role

• You finish things, not just start them.
• You read existing code first and match its patterns — surgical changes over rewrites.
• You are comfortable with ambiguity (requirements evolve, regulations change, priorities shift).
• You take ownership instead of waiting for perfect specs.
• You explain technical decisions through reasoning and impact, not authority.
• You focus on delivering working, maintainable systems rather than concepts.

What We Offer

• Competitive compensation aligned with seniority
• Private health insurance
• Fit Pass Premium membership
• Hybrid work arrangement
• Complex, meaningful fintech projects — payments, banking, and crypto in one platform

Why This Role Exists

Our platform handles client wallets and ledgers, IBAN and wallet payments, crypto custody and exchange, and regulated financial flows across multiple tenants. Performance, reliability, and clarity matter — every day, not just during releases. Every fee, every settlement, and every reconciliation has to be exact. You’ll build systems that scale, operate reliably in production, meet regulatory requirements, and remain readable and maintainable over time.

How to Apply

Apply by sending your CV. We thank all applicants for their interest; however, only shortlisted candidates will be contacted.