Intermediate Backend C#/.NET Engineer

What is the role?

Protium is looking for an Intermediate Backend C#/.NET Engineer to help us build and ship production APIs, services, integrations, and backend systems using C#, .NET, SQL Server, and Microsoft/Azure technologies.

This is a Cape Town–based hybrid role, with in-person office days typically 2–3× per week at our Claremont office.

You’ll work on high-quality, API-driven systems where attention to detail matters: clean architecture, maintainability, performance, security, scalability, and long-term supportability.

While this is primarily a backend engineering role, we value developers who are comfortable working across the stack when needed, whether that means understanding frontend integration requirements, contributing to web application features, debugging end-to-end flows, or collaborating closely with frontend and mobile engineers.

About Protium

Protium is a security-first software development company based in Claremont, South Africa.
We build robust, scalable, future-proof software with a strong emphasis on engineering standards, clean delivery, practical architecture, and long-term maintainability.

Our work is primarily focused on building high-quality software systems for clients in the financial services sector (but not limited to), where reliability, security, correctness, and clear communication matter.

Working model

• Cape Town based
• Hybrid
• Office meetups: typically 2–3× per week
• Full-time preferred
• Contract-to-perm considered
• Positions available: 3

This is not a fully remote role. You should be based in Cape Town and able to attend regular in-person office days in Claremont.

About you

You’re at that sweet spot: strong enough to own backend features end-to-end without hand-holding, but still hungry to learn, improve, and sharpen your craft.

You are comfortable taking architectural direction, understanding abstract technical designs, and turning them into clean, maintainable production code. You care about good engineering principles, including SOLID, sensible abstractions, design patterns where appropriate, testability, and clear separation of concerns.

You take ownership of your work. You ask good questions, raise risks early, communicate clearly, and collaborate well with other developers, architects, QA, designers, and client stakeholders.

You use AI-assisted engineering tools in your day-to-day work as a serious productivity lever, not as “vibe coding”, but as a way to accelerate delivery while keeping code quality high. You still think critically about design, correctness, readability, tests, maintainability, and security.

What you’ll do

• Build and maintain production-grade APIs & Services using C# and .NET.
• Design and implement backend services, business logic, integrations, and data access layers.
• Work with SQL Server databases, including schema design, queries, stored procedures where appropriate, and performance considerations.
• Build integrations with internal and external systems using REST APIs, messaging, scheduled jobs, file-based integrations, and other pragmatic integration patterns.
• Translate architectural designs and technical direction into clean, maintainable code.
• Contribute to system design discussions, technical trade-off decisions, and implementation planning.
• Write and maintain automated tests for core backend logic and integration points.
• Debug, diagnose, and resolve issues across backend services, databases, APIs, and client-facing flows.
• Collaborate with frontend, mobile, QA, and product stakeholders to deliver complete working features.
• Participate in code reviews and help maintain strong engineering standards.
• Contribute to CI/CD pipelines, deployment processes, and operational improvements where needed.
• Use AI-assisted engineering tools responsibly to improve delivery speed, feedback loops, and code quality.

Requirements

• Strong experience with C# and .NET / ASP.NET Core.
• Solid experience building and maintaining REST APIs.
• Good understanding of SQL Server and relational database design.
• Experience with data access patterns using tools such as Entity Framework Core, Dapper, or similar.
• Good understanding of backend architecture, layering, separation of concerns, and maintainable service design.
• Comfortable working with authentication, authorisation, validation, error handling, logging, and API security basics.
• Strong engineering habits: clean code, good abstractions, sensible trade-offs, and a quality mindset.
• Ability to understand technical designs and turn them into working production code.
• Ability to own features end-to-end, from implementation through to testing and release support.
• Comfortable using Git and working in a collaborative development workflow.
• Comfortable with code reviews, technical discussions, and constructive feedback.
• Cape Town based and available for regular office meetups in Claremont.
• Comfortable using AI-assisted engineering tools as a productivity lever, while still applying strong judgement around design, correctness, readability, testing, maintainability, and security (i.e. not a crutch).

Tech stack you should be comfortable with

We expect hands-on experience in several of the following:

Core requirements

• C#/.NET
• REST APIs
• SQL Server, Entity Framework Core and/or Dapper
• Git
• Backend fundamentals & design patterns
• Ownership and communication

Expected to grow into / useful experience

• Azure & Azure DevOps
• Docker
• CI/CD
• Messaging or event-driven systems
• Background services / worker services
• API authentication and authorisation patterns
• Observability

You do not need to be an expert in everything listed, but you should have strong backend fundamentals and be comfortable learning new tools and patterns quickly.

Nice-to-have (not required)

• Full-stack development experience with web technologies such as React, TypeScript, HTML, CSS, or similar.
• Experience with MVC, Razor Pages, Blazor, or other .NET-based web application patterns.
• Experience in a secondary backend language such as Node.js, Java, Python, or similar.
• Experience with messaging technologies such as RabbitMQ, LavinMQ, Kafka, Azure Service Bus, or similar.
• Experience with event-driven architecture, pub/sub patterns, fanout, retries, reconnect strategies, and topic design.
• Experience building secure portals, financial services systems, reporting systems, workflow systems, or integration-heavy platforms.
• Familiarity with cloud hosting, especially Azure.
• Experience with infrastructure, observability, logging, monitoring, or production support.
• Experience working in consulting, agency, or client-facing delivery environments.
• Experience helping shape technical decisions, not just implementing tickets.

Security mindset

You don’t need to be a security specialist, but you should have a strong baseline of secure engineering practices for web applications, mobile applications, and API integrations, and you should be comfortable discussing those practices during interviews. Security, quality, and maintainability are important parts of how we build software at Protium.

Compensation & benefits

Market related — we offer competitive salaries and meaningful employee benefits.

Final compensation will depend on experience, seniority, technical depth, and fit for the role. Benefits and employment structure will be discussed during the hiring process.

Hiring process (what to expect)

1. CV review + short Protium-specific motivation or cover letter
2. Get-to-know-you call
3. Technical interview
4. Optional: Short take-home assignment
   A focused backend/API task based on a small base project, targeted at approximately 2–4 hours
5. Optional: live extension or bug-fix session
   A short 30–45 minute session to see how you approach problems, reason through trade-offs, and use AI-assisted engineering tools while keeping quality high

We aim to keep the process pragmatic and respectful of your time. Depending on the role and your background, some stages may be shortened, combined, or skipped.

How to apply

Send us:

• Your CV
• A short Protium-specific motivation. 3–6 sentences is enough
• Links to GitHub, GitLab, shipped projects, APIs, technical writing, or other relevant work (optional, but recommended)