.NET Developer

The client is a London-based fintech on a mission to empower corporate finance teams with institutional-grade tools for FX analytics, risk management, execution, and cross-border payments. Their self-service SaaS platform brings transparency, control, and cost-efficiency to foreign exchange processes—capabilities traditionally reserved for large banks and hedge funds. The client emphasizes a tech-first, data-driven approach, without offering financial advice.    

• Develop and maintain high-performance .NET-based solutions with a strong focus on architecture, scalability, and security

• Build RESTful APIs, work with CI/CD pipelines, and apply TDD

• Implement modern architecture patterns (Ports & Adapters, Clean Architecture, Pub/Sub)

• Collaborate closely with the team: perform code reviews, mentor peers, and promote best practices

• Work with SQL Server (query optimization, stored procedures), Azure, and RabbitMQ/Azure Service Bus

• 5+ years of experience with .NET and .NET core (C#): We expect you to have in-depth knowledge including such aspects as multithreading, concurrency, asynchronousity, optimization techniques (Span, Memory, Slices, ArrayPool, ObjectPool), and in-depth understanding of memory management. We pay special attention to new features delivered in new versions of .NET.

• Web & API Frameworks: ASP.NET Core, Minimal APIs, gRPC. Special requirements include understanding middleware, dependency injection (DI), proper lifecycle management, and best practices for designing RESTful services.

• English level — Upper-Intermediate+ (B2+)

• Proven experience in backend development with a focus on architecture, performance, and security

• Building RESTful APIs, CI/CD pipelines, and unit testing (TDD) (xUnit, NUnit, MSTest, Moq, NSubstitute, FakeItEasy, AutoFixture, Bogus, BenchmarkDotNet, NBomber. Know and use testing not just to get a good number of code coverage, but to write tests that actually catch bugs. Have in-depth knowledge of scenarios working with mocking libraries.)

• Solid understanding of SOLID principles, design patterns, and Ports & Adapters architecture

• SQL Server: query optimization, Entity Framework, stored procedures (SQL Server, MongoDB, Cosmos DB, Redis. The solution heavily relies on SQL Server, so we expect you to know advanced concepts like isolation levels of transactions, cancellation tokens (CTS), stored procedures, views, query analysis, execution plans, optimizations, internals of indexing, partitioning, and collations.)

• Code quality and reviews: Strong advocate for clean code principles, with extensive experience in conducting code reviews and driving best practices across the development team.

• Experience with Angular / TypeScript

• Experience with F# (or a strong understanding of functional programming principles)

• Experience with Akka.NET, actor model, and distributed systems

• Identity & Security: ASP.NET Identity, JWT, OAuth2, OpenID Connect. Have in-depth knowledge of all of these identity strategies. Hands-on experience setting them up from scratch and understanding how a server can manage permissions

• Experience with financial services integrations: FIX protocol, SWIFT, payment systems

• Cosmos DB, Azure Functions

• Comfortable using AI-assisted tools (e.g., GitHub Copilot, ChatGPT, Notion AI) for boosting productivity

• A competitive salary that appreciates your skills and experience

• Cozy atmosphere and modern approaches. We have neither bureaucracy nor strict management nor “working under pressure” conditions

• Opportunity to implement your ideas, tools, and approaches. We are open to changes and suggestions aimed at improvement