Senior C#.Net Developer

Dearx; Johannesburg; On-site; ZAR 300,000 - 400,000; Part time

Job summary

A leading tech company in Johannesburg is seeking an experienced Senior C# .NET Engineer to develop trading and risk platforms for global markets. This is an on-site position focused on creating high-performance systems that are critical to trading operations. Candidates should have over 7 years of development experience, familiarity with complex systems, and a passion for problem-solving in a collaborative environment.

Qualifications

• 7+ years of professional C# .NET development experience.
• Mastery of object-oriented design, SOLID principles, and design patterns.
• Strong experience with RESTful APIs, microservices, and distributed systems.
• Skilled with DevOps automation, CI/CD pipelines, and monitoring.

Responsibilities

• Build pricing & risk engines used by trading desks and risk officers.
• Develop high-performance microservices and REST APIs.
• Ensure complex scheduling, orchestration, monitoring, and alerting systems.

Skills

C# .NET development

Object-oriented design

RESTful APIs

Microservices

DevOps automation

Problem-solving skills

Attention to detail

Tools

AWS

Kafka

RabbitMQ

Job description

DeARX Johannesburg, Gauteng, South Africa

Senior C# .NET Engineer

Build trading & risk platforms for global markets

Location: Sandton, Johannesburg (On-site)

Contract: 6 months (with strong chance of renewal / long-term engagement)

Level: Senior / Specialist

Be part of something bigger. We're hiring an exceptional Senior C# .NET Engineer to join a highly specialized team building a world-class trading, pricing, and risk platform for global markets.

This is a chance to build real-time systems that power trading desks, market risk, and credit systems where performance, reliability, and precision matter. If you're passionate about complex problem-solving, clean architecture, and seeing your code directly impact global financial markets, this role was built for you.

What You'll Be Building

• Pricing & risk engines used by trading desks and risk officers
• High-performance microservices, REST APIs, and distributed systems
• Client applications (WPF), web portals (Blazor), and Excel DNA integrations
• Cloud migrations to AWS (scaling fast)
• Complex scheduling, orchestration, monitoring, and alerting systems

Why This Role Is Different

• Direct impact: What you build gets used daily by market makers, traders & risk managers.
• High autonomy: You’ll be part of a senior, collaborative team where your input shapes architecture & design.
• Real complexity: Large-scale, real-time financial data systems with millions of calculations daily.
• Elite environment: Surrounded by sharp, like-minded engineers passionate about clean code, elegant design, and systems that just work.

What We're Looking For

• 7+ years of professional C# .NET development experience
• Mastery of object-oriented design, SOLID principles, and design patterns
• Strong experience with RESTful APIs, microservices, and distributed systems
• Skilled with DevOps automation, CI/CD pipelines, and monitoring
• Excellent problem-solving skills and attention to detail
• Comfortable working directly with business stakeholders to shape solutions

Bonus Points If You Have

• Financial services / trading / risk system experience
• AWS experience (migrations, serverless, compute scaling)
• Messaging protocols (Kafka, RabbitMQ)
• Excel DNA (or Excel Add-ins development)

Sample Screening Questions

• Explain SOLID principles in your own words.
• How would you design an immutable system in C#?
• Describe how you use generics effectively in .NET.

You build the system. The system drives the market.

Ready to engineer software that actually powers financial markets? Apply today or email me.

Note: Must be US Citizens or have a valid critical skills permit in own name.

Additional Details

• Seniority level: Mid-Senior level
• Employment type: Contract
• Job function: Engineering and IT
• Industries: IT Services and IT Consulting

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