ZEN247 - Senior .NET Developer

Job Summary

Our client is seeking two Senior .NET Developers to build and enhance scalable, high-performance systems within a distributed microservices architecture. The successful candidates will bring expert-level proficiency in .NET 8+ and C# 12+, strong SQL Server and ORM performance capability, and experience with event-driven services, modern API design, Azure DevOps delivery and automated testing. This role also requires production ownership, technical leadership, sound architectural judgement and the ability to guide engineering teams through complex delivery and operational challenges.

Responsibilities

• Build and enhance scalable systems within a distributed microservices architecture.

• Design and implement RESTful and gRPC APIs with strong documentation, versioning and backward-compatibility standards.

• Develop event-driven services using RabbitMQ, Kafka or Azure Service Bus to support high-volume asynchronous workloads.

• Design and optimise SQL Server databases, queries and indexes for ultra-high-throughput environments.

• Select and use Dapper or Entity Framework Core appropriately, balancing maintainability, control and performance.

• Implement advanced caching patterns where required to reduce latency and improve system performance.

• Design advanced Azure DevOps pipelines, manage releases and apply blue-green, canary or other modern deployment strategies.

• Drive code quality through rigorous reviews, SOLID principles, design patterns, refactoring and engineering standards.

• Lead the adoption of unit, integration, contract and load-testing practices across the development lifecycle.

• Profile, optimise and debug complex application and production-performance scenarios.

• Lead incident response, post-mortems and operational improvement efforts during high-severity production challenges.

• Lead technical design discussions, influence architecture and identify opportunities for system modernisation.

• Mentor junior and mid-level developers and support their technical growth.

Competencies

• Excellent technical communication, with the ability to explain complex concepts to diverse audiences.

• Strong ownership mindset with accountability for outcomes, service reliability and production quality.

• Ability to influence architectural and engineering decisions without relying on formal authority.

• Adaptable, proactive and solution-driven in a fast-moving environment with changing priorities.

• Collaborative and team-oriented, with effective cross-functional communication.

• Resilient and composed under pressure, particularly during high-severity production incidents.

• High attention to detail, especially when working in regulated environments.

Technical Skills

• Strong Expert-level proficiency in .NET 8+ and C# 12+, including async/await, LINQ, reflection and performance tuning, is mandatory.

• Strong Dapper and Entity Framework Core experience, including ORM trade-offs and performance tuning, is mandatory.

• Advanced SQL Server capability in query tuning, indexing, execution plans and statistics is mandatory.

• Strong microservices design experience covering service boundaries, communication patterns and reliability is mandatory.

• Event-driven architecture experience using RabbitMQ, Kafka or Azure Service Bus is mandatory.

• Strong REST and gRPC API design experience, including backward compatibility and versioning strategies, is mandatory.

• Advanced Azure DevOps pipeline design and release-management experience is mandatory.

• Understanding of modern deployment strategies, including blue-green and canary deployment, mandatory.

• Deep automated-testing experience across unit, integration, contract and load-testing layers is mandatory.

• Strong knowledge of SOLID principles, design patterns and refactoring practices is mandatory.

• Performance profiling, optimisation and complex debugging capability is mandatory.

• Experience leading incident response, post-mortems and operational improvements is mandatory.

• Deep understanding of ACID, isolation levels, deadlocks, sharding and partitioning is advantageous.

• Redis expertise in distributed caching and cache-invalidation strategies is advantageous.

• Elasticsearch experience covering indexing, search and aggregation performance optimisation is advantageous.

• Experience with logging, tracing and performance monitoring using OpenTelemetry is advantageous.

General Information

• Contract: Until 31 March 2027

• Location: Johannesburg

• Work Mode: Hybrid - 4 days per week in the office