Senior .NET Developer - Microservices & APIs

Introduction

ID: 32520

Contract Details

• Location: Johannesburg

• Working arrangement: Hybrid, in accordance with the client’s remote-working protocols

• Contract period: 1 September 2026 to 28 February 2027

• Employment type: Six-month contract

• Industry: Corporate and Investment Banking

We are seeking an accomplished Senior .NET Developer to join a strategic lending transformation programme within Corporate and Investment Banking.

The successful candidate will design and develop the backend services, APIs and integrations supporting digital deal intake, task management, document management, collaboration, deal tracking and AI-enabled capabilities.

This role requires a senior engineer who can design robust service patterns, make architectural decisions and develop secure, scalable and auditable solutions within a complex enterprise environment.

Duties & Responsibilities

• Design, develop and maintain backend services using C# and .NET.

• Define appropriate microservice boundaries using bounded-context and single-responsibility principles.

• Design RESTful APIs with effective versioning, validation and error-handling standards.

• Build API Gateway services that aggregate multiple microservice calls into client-consumable views.

• Develop secure integrations with internal and external enterprise platforms.

• Implement synchronous REST and asynchronous messaging patterns.

• Design PostgreSQL data models and optimise database performance.

• Implement authentication, authorisation and entitlement controls.

• Develop audit and event-logging capabilities that ensure all actions are traceable.

• Create reliable unit and integration tests.

• Implement correlation IDs, centralised logging and distributed tracing.

• Troubleshoot complex issues across distributed systems.

• Collaborate with Angular, Python, AI and cloud engineers.

• Conduct code reviews and mentor other developers.

• Participate in architectural discussions, PI planning and Agile delivery.

• Support the secure integration of AI and document-generation services.

Desired Experience & Qualification

Essential Requirements

• Approximately eight or more years of software engineering experience.

• Advanced C# and .NET development experience.

• Strong experience designing and implementing microservices.

• Excellent understanding of RESTful API design and versioning.

• Experience with API Gateway and enterprise integration patterns.

• Knowledge of synchronous and asynchronous service communication.

• Strong PostgreSQL or relational database experience.

• Experience implementing authentication and authorisation controls.

• Practical knowledge of audit logging and event-driven systems.

• Strong unit-testing and integration-testing experience.

• Experience diagnosing problems across distributed systems.

• Ability to contribute to architectural decisions and mentor other engineers.

Advantageous Experience

• Python development.

• AWS IAM, VPC, S3 and CloudWatch.

• CloudWatch X-Ray or equivalent distributed-tracing technologies.

• Grafana and Loki.

• Document-management or automated document-generation solutions.

• LLM or Generative AI service integration.

• Investment banking, lending or financial-services experience.

• CI/CD and DevOps automation.

• SAFe, Agile Release Trains or PI planning.

Interested?

The ideal candidate is a senior backend engineer who combines strong hands-on .NET development with sound architectural judgement. The individual should understand secure enterprise integration, auditability and distributed-system reliability and be able to guide other developers when required.