Backend .NET Engineer - USSD & Telco Charging

About the role

ServTech Rwanda is seeking a Backend .NET Engineer to design and build large‑scale backend services that power USSD menus and telco charging platforms across Africa. You will own the full product lifecycle, from initial scoping through deployment and continuous optimisation.

Key responsibilities

• Design, implement and maintain high‑performance, stateless backend services using C#/.NET Core.
• Develop USSD menus, short‑code flows and charging engines that integrate with Rwandan MNOs such as MTN and Airtel.
• Build secure, low‑latency APIs and adapters for USSD gateways, charging platforms and mobile‑money wallets while ensuring compliance with local regulations.
• Optimize concurrency, rate limiting, back‑pressure and circuit‑breaking to achieve strong uptime and speed.
• Improve CI/CD pipelines, automated testing and observability tooling.
• Collaborate with Product, Design and Business Intelligence teams to deliver business‑critical features.

Required profile

• 6+ years of advanced C#/.NET development experience, strong in .NET Core.
• Proven experience delivering USSD services or telco charging integrations in Rwanda.
• Excellent English communication skills.

Required skills

• C# and .NET Core
• SQL (schema design, complex queries, stored procedures)
• Docker
• CI/CD pipelines and automated testing
• Public cloud platforms (AWS preferred)
• Redis or similar NoSQL store
• Performance diagnostics and tuning (profiling, memory/CPU, DB, cache)
• RESTful API design, caching, messaging
• USSD integration and telco charging workflows
• Mobile Money integration, SMPP/SMS gateways (nice to have)
• OAuth2/OpenID Connect (nice to have)
• Observability tools such as Prometheus, Grafana, OpenTelemetry (nice to have)