Senior Full Stack .NET Developer - Enterprise Applications & Integrations
Help Evolve a Business-Critical Enterprise Software Platform
Existco is looking for an experienced Senior .NET Developer to join our team and play a key role in the ongoing evolution of ExPCS (Existco Plant Control System), our enterprise manufacturing and distribution platform used by food manufacturers, processors, wholesalers, distributors and logistics businesses nationwide and internationally.
This is a unique opportunity to work on a mature, feature-rich software platform that supports real-world business operations every day, while helping shape its next generation.
A significant part of the role will involve enhancing, maintaining and extending our existing VB.NET, WinForms, SQL Server and Windows Services platform. You'll also collaborate with the team as we progressively evolve ExPCS into a modern API-first ecosystem spanning web, mobile, cloud and desktop technologies.
We're looking for someone who enjoys complex business systems, solving practical operational challenges and building software that delivers meaningful outcomes.
Why This Role Is Different
Work on a business-critical enterprise platform with significant real-world complexity
Be involved in both maintaining and modernising a substantial software product
Work across desktop, web, mobile, cloud and integration projects
Collaborate directly with customers, product stakeholders and decision-makers
Gain exposure to manufacturing, warehousing, logistics, inventory and ERP workflows
Help shape the future direction of a platform with an established customer base
What You'll Be Doing
Maintain, enhance and support the existing ExPCS platform
Develop new features across desktop, web and mobile applications
Design and implement APIs, integrations and backend services
Support and extend integrations with ERP, accounting and third-party systems
Work with SQL Server databases and high-volume transactional systems
Contribute to the gradual modernisation of legacy applications and services
Collaborate on architecture, platform improvements and future product direction
Troubleshoot and resolve complex technical challenges




Technology Workplace
Current Platform
Platform Evolution
You don't need experience across every technology listed above. Strong enterprise software experience, problem-solving ability and a willingness to work across both established and emerging technologies are more important.
What We're Looking For
8+ years commercial software development experience
Strong C# and .NET capability
Experience with enterprise or line-of-business applications
Experience designing and implementing REST APIs
Experience integrating software with external systems
Strong troubleshooting and analytical skills
Excellent collaboration and communication skills
Highly Regarded
VB.NET and WinForms experience
Experience maintaining large, long-lived software platforms
ERP, manufacturing, warehousing or logistics systems
Accounting software integrations (MYOB Exo, MYOB Advanced, Xero, etc.)
Third‐party API and integration experience
Azure and mobile development experience
Why Join Existco?
We're a collaborative, highly engaged team where your ideas and technical input genuinely influence outcomes.
You'll work alongside experienced product specialists, customers and decision-makers while contributing to both the current platform and its future direction.
This is an opportunity to leave a long‐term mark on a product that powers critical business operations every day.
About ExPCS
ExPCS is a specialised manufacturing and ERP platform developed for food manufacturers, processors, distributors and logistics businesses.
Key capabilities include:
Warehouse & Inventory Control
Batch & Lot Traceability
Quality Assurance
Third‐Party Integrations
$100,000 - $120,000 + Superannuation
(Dependent on experience, architecture capability, and demonstrated leadership)




QUALIFICATION QUESTIONS (please include in cover letter)
How many years of commercial software development experience do you have using Microsoft technologies (.NET, C#, VB.NET, SQL Server)?
Less than 5 years
5-8 years
8-12 years
***** years
15+ years
Which of the following technologies have you used professionally? (Select all that apply)
C#
VB.NET
WinForms
.NET Framework
Modern .NET (.NET Core / .NET)
SQL Server
REST APIs
Azure
Windows Services
MAUI / Xamarin
Vue.js
TypeScript
What best describes your experience with enterprise or line-of-business software applications?
No experience
Limited exposure
Regular contributor
Primary developer
Technical owner / subject matter expert
Have you been involved in maintaining, modernising or evolving a legacy software platform?
No
Minor contribution
Significant contributor
Led major components
Which of the following business systems have you worked on professionally? (Select all that apply)
ERP
Manufacturing Systems
Warehouse Management Systems (WMS)
Supply Chain / Logistics
Inventory Management
Accounting / Finance Systems
Retail Systems
SaaS Platforms
Other Enterprise Applications
What is your level of experience designing and implementing APIs and software integrations?
None
Basic
Intermediate
Advanced
Expert
Which integration types have you worked with? (Select all that apply)
Accounting Software Integrations
ERP Integrations
Third‐Party APIs
Web Services
Data Import / Export Processes
EDI Integrations
Warehouse Systems
Event‐Driven Integrations
Please describe the largest enterprise software platform you have maintained, enhanced or modernised, including:
Technology stack
Your role
Number of users
Key business functions supported
What interests you most about this role?
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 Developer - Enterprise Applications & Integrations (Western Australia)
🏢 Existco
📍 Western Australia