Senior .NET Backend Architect

Contracting via SigmaSoft from the Sunshine Coast

I build the systems other developers build on – integration layers, meta-schema engines, API frameworks. The kind of backend work that makes a team of three move like a team of ten. 25 years of commercial delivery. Remote-first. Available for contract engagements through SigmaSoft (AU ABN entity).

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Cobus Lombard, Senior .NET Backend Architect

Smarter Systems. Faster Teams.

I'm Cobus Lombard – a Senior .NET Backend Architect with 25 years of commercial delivery, contracting through SigmaSoft from the Sunshine Coast, QLD.

I specialise in the backend infrastructure other developers build on: integration layers, schema-driven frameworks, event-driven architectures, and API conventions. When I design a system, the team behind it moves faster because the hard decisions are already made correctly.

Most recently at ConnX (Brisbane), I led a three-person team building two foundational capabilities for a B2B HR/payroll SaaS: a provider-agnostic payroll integration layer (MassTransit + Saga State) and a meta-schema engine that enabled a 600+ page modernisation project. Both shipped ahead of estimate.

Remote-first. Autonomous. Available for 6–12+ month contract engagements.

Senior .NET Backend Architect workspace

Core Stack

.NET & Backend Architecture

C#, .NET 6/8/10, ASP.NET Core Web API, Entity Framework Core. Specialising in provider-agnostic integration layers, event-driven systems, and API-first design.

  • MassTransit + Saga State pattern
  • Enterprise Service Bus (ESB)
  • Schema-driven API design
  • Provider-agnostic integration
  • Azure Service Bus

Azure & Cloud Infrastructure

Azure-native delivery from CI/CD pipelines to production. DevOps-first – every engagement ships with repeatable build and deploy.

  • Azure Functions + Durable Functions
  • Azure App Services + SQL Server
  • Azure DevOps + GitHub Actions
  • CI/CD (YAML pipelines)
  • Azure Service Bus

Data & Integration

SQL Server design, T-SQL optimisation, and integration architecture. Schema design through to cross-system synchronisation.

  • SQL Server design + T-SQL
  • Entity Framework Core
  • REST API conventions
  • Vue.js (frontend support)
  • Cross-system integration

Proof, Not Promises

78% Faster Provider Onboarding

At ConnX, designed a provider-agnostic payroll integration layer using MassTransit and the Saga State pattern. First provider: 18 months (platform build included). Second provider: 4 months – same framework, reused wholesale. The framework scales to any additional provider without architectural rework.

4 Days vs. Several Weeks Per Page

Architected a meta-schema engine at ConnX where the backend drives frontend layout, validation, and permissions server-side. First data-intensive page delivered in 4 days against an estimated several weeks. That framework now sits under a 600+ page modernisation project, and no page needs its own frontend code.

7-Year Production SaaS, Built Solo

GasKit (gaskit.co.za) – LP gas telemetry and billing for 300 commercial and 3,000 residential customers across South Africa – has run continuously and profitably since late 2018. No co-founder. No agency. Sole developer, architect, operator, and support function throughout.

What Clients Say

What distinguishes Cobus from many senior developers is his natural instinct for future-proofing and managing technical debt. He consistently thinks beyond the immediate ticket, designing solutions that remain maintainable and extensible as the product evolves. This discipline saved the team significant rework on multiple occasions and reflected a maturity of engineering thinking that is genuinely rare. Cobus operates with a high degree of autonomy – once aligned on the intent of a piece of work, he can be trusted to see it through to completion with the appropriate level of quality.

Dallas Fett Team Leader – Product, ConnX Pty Ltd

Cobus played a pivotal role as the main developer on a strategic project enabling connections to various payroll systems through an API. His technical expertise and innovative approach were instrumental in the successful implementation of this project, which has significantly improved our product offerings and client satisfaction. Beyond his technical skills, Cobus has been a great mentor to both junior and senior developers, consistently providing guidance, support, and knowledge-sharing within our team.

Dan Cresswell Head of Product, ConnX Pty Ltd

Nothing in our business gets done without SigmaSoft's tech solution, GasKit, being installed. Moving over to IoT has been a gamechanger. We've streamlined our systems, reduced expenses, and become significantly more efficient. As a bonus, we now transact with a clientele we couldn't have before - we no longer just sell gas, we now sell a service.

Nolan Cohen CEO, Indigas

It has been great working with SigmaSoft integrating IoT devices to a proprietary software platform which they developed from scratch. Ongoing changes were made during the development process, reflecting their flexibility to customise a package to suit client needs. Collaboration throughout the development stage went seamlessly, which ultimately led to a commercially available solution we can offer our End User clients.

Karl Wigginton Director, Aquamonitor

Available for Contract

Remote-first. Sunshine Coast, QLD.

Senior .NET backend contract work through SigmaSoft (AU ABN entity). I take ownership of ambiguous technical problems without requiring heavy direction. If you have a backend-heavy engagement – integration work, modernisation, API architecture – let's talk. Engagements of 6–12+ months preferred.

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Location

1st Floor, 100 Brisbane Road
Mooloolaba, QLD

Email

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Phone

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Availability

Open to new engagements. Response within 24 hours.