Senior Developer (Backend) - C# .NET

Sygnia is an innovative FinTech company based in South Africa and listed on the main board of the JSE. The company provides asset management, stockbroking and administration services, as well as a wide range of savings products, to institutional and retail clients. All that we do is supported by leading-edge technology platforms. Sygnia offers a dynamic, fast-paced, and growth-focused environment that values innovation, accountability, and continuous improvement. Employees are encouraged to be curious, take ownership, and contribute meaningfully to a collaborative and performance-driven culture.

We’re hiring a senior backend-focused .NET engineer to work across legacy .NET Framework (C#, VB.NET, WPF, WCF/NetTcp) and modern .NET with gRPC. You’ll design clean, maintainable, well-tested services, solve complex problems, and collaborate closely with the team. Some front-end work in WPF is part of the role; exposure to Blazor and JavaScript is welcome. The role is office based in Cape Town, with working in office Monday – Friday.

The duties and responsibilities of this position include (but are not limited to):

• Build and evolve backend services on .NET Framework and modern .NET with strong contracts, reliability, and testability.
• WCF (NetTcp): maintain/extend contracts, behaviours, diagnostics, and hosting.
• gRPC: define protobuf contracts; implement servers/clients; use streaming, deadlines, and interceptors where appropriate.
• Desktop & UI: contribute to WPF modules using MVVM; maintain clean UI–service boundaries.
• Optional web UI: occasional Blazor components and light JavaScript when useful.
• Engineering discipline: uphold coding conventions, SOLID, unit/integration tests, and meaningful code reviews.
• Delivery: work in Jira; keep TeamCity builds green; follow disciplined SVN branching/merging.

Qualifications and Experience:

• Languages & runtimes: Expert C#; competent VB.NET for legacy components; .NET Framework 4.x and modern .NET (6/7/8+).
• RPC stacks: WCF (NetTcpBinding) and gRPC (contract-first, protobuf, streaming).
• WPF (MVVM): bindings, commanding, data templates, resource dictionaries.
• Architecture & quality: SOLID principles, dependency injection, async/await, structured logging, exception strategy, meaningful tests.
• Tooling: Visual Studio 2022, Jira, SVN, TeamCity.
• Blazor (Server/WASM) fundamentals; pragmatic JavaScript/TypeScript for interop.
• Performance profiling, memory diagnostics, concurrency tuning.
• Secure RPC communications (certs, transport security) and migration experience between WCF and gRPC.
• 8–10 years professional .NET development with significant backend experience.
• Production experience with WCF (NetTcp) and WPF on .NET Framework, plus gRPC on modern .NET.
• Demonstrable application of SOLID and common design patterns in real systems; adherence to coding conventions.

Disclaimer: please be advised that your personal information shared on your CV will only be used as part of the Sygnia recruitment process for the role applied for. It will not be shared with any third parties for any other reason.