Senior Full Stack .
NET and Web Developer
Existco is seeking an experienced Senior Full Stack .
NET Developer to lead the next generation redesign and modernization of our ExPCS Existco Plant Control System (ExPCS), a comprehensive ERP and manufacturing platform used within the food manufacturing, processing, wholesale distribution, and logistics industries.
We are looking for a highly capable senior developer and software architect who can help transform a mature, business-critical platform built on VB.NET, WinForms, Xamarin, SQL Server, and Windows Services into a modern API-driven architecture leveraging web, desktop, mobile, cloud, and distributed technologies.
You will work directly with executive leadership, product owners, and customers to shape the long-term technical direction of the platform.
Key Responsibilities
Lead the technical architecture and modernization of the Existco Plant Control System platform
Design scalable backend services and API infrastructure
Build modern desktop, web, and mobile applications
Refactor legacy applications into service-oriented architecture
Design and implement domain-driven business objects and repositories
Improve existing application performance, reliability, and maintainability
Develop integration frameworks for third-party platforms
Mentor junior developers and provide technical leadership
Participate in strategic product planning and roadmap development
Collaborate with business stakeholders to translate complex operational requirements into software solutions
Maintain and migrate existing platform until depreciation.
Required Skills & Experience
10+ years commercial software development experience
Strong C# and .
NET development expertise
Experience designing large-scale enterprise applications
Strong SQL Server and database design knowledge
Experience with REST API development
Experience with Azure cloud services
Strong understanding of software architecture patterns




Experience with object-oriented design principles
Knowledge of source control, CI/CD, and automated deployments
Understanding of accounting principles, ERP Systems and Warehouse Management Systems
Excellent problem-solving and communication skills
Highly Desirable Skills
What Success Looks Like
Within your first 12 months, you will help define and execute:
The migration strategy from the legacy platform
Design of the new API and service layer
Modernization of desktop applications
Mobile application architecture roadmap
Scalable integration platform for customers and partners
Improved cloud deployment and monitoring capabilities
Why Join Existco?
Opportunity to architect a major business-critical platform from the ground up
Work directly with executive leadership and product stakeholders
Influence technology decisions and product direction
Exposure to cloud, desktop, web, mobile, and enterprise architecture
Long-term product ownership and technical leadership opportunities
Market-competitive salary package based on experience
Salary Guide
$100,000 - $120,000 + Superannuation
(Dependent on experience, architecture capability, and demonstrated leadership)
Qualification Questions
How many years of commercial software development experience do you have using .
NET technologies?
Less than 5 years
5-10 years
***** years
15+ years
Have you led the design, architecture, or modernization of a large-scale enterprise software platform?
Yes
No
If yes, please briefly describe the project.




Which of the following technologies have you used professionally?
(Select all that apply)
C#
.NET Framework / .
NET Core
SQL Server
Azure
REST APIs
WinForms
VB.NET
MAUI / Xamarin
Vue.js
Electron
Node.js
TypeScript
What is your level of experience designing and implementing REST API architectures?
None
Basic
Intermediate
Advanced
Expert / Architect
Have you designed or implemented solutions using any of the following architectural patterns?
(Select all that apply)
Domain-Driven Design (DDD)
CQRS
Event-Driven Architecture
Microservices
Repository Pattern
None of the above
What experience do you have migrating legacy applications to modern architectures?
Please provide a brief example including technologies used and your role in the project.
Which industries have you developed enterprise software for?
(Select all that apply)
Manufacturing
ERP
Wholesale Distribution
Warehousing
Logistics / Supply Chain
Accounting / Finance
Retail
Other
Have you been responsible for mentoring developers or leading a software development team?
No
Informal Mentoring
Technical Lead
Development Manager
Solution Architect / Principal Engineer
Please describe the largest software system you have designed, modernized, or maintained, including:
Number of users
Technology stack
Your role
Key business functions supported
This role requires working directly with executive leadership and helping define long-term product strategy.
Which best describes your experience?
Developer only
Senior Developer
Technical Lead
Solution Architect
Principal Architect / CTO-level responsibilities
Bonus Question (Highly Recommended)
Why are you interested in leading the modernization of the ExPCS platform, and what would be your high-level approach to transforming a legacy VB.NET/WinForms system into a modern API-first architecture?
#J-*****-Ljbffr

📌 Senior Full Stack.Net And Web Developer (Western Australia)
🏢 Existco
📍 Western Australia