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 Environment

Current Platform

• VB.NET

• WinForms

• C#

• .NET Framework

• SQL Server

• Windows Services

• REST APIs

• Xamarin

Platform Evolution

• Modern .NET

• Azure

• Vue.js

• TypeScript

• MAUI

• Electron

• API-First Architectures

• Cloud Services

• CI/CD Pipelines

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

Essential

• 8+ years commercial software development experience

• Strong C# and .NET capability

• Experience with enterprise or line-of-business applications

• Strong SQL Server skills

• 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

• Legacy modernisation projects

• 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:

• Production Management

• Warehouse & Inventory Control

• Batch & Lot Traceability

• Quality Assurance

• Purchasing & Receivables

• Product Costing

• Logistics & Dispatch

• Third-Party Integrations

Salary

$100,000 - $120,000 + Superannuation

(Dependent on experience, architecture capability, and demonstrated leadership)

How to Apply

Submit your Resume and a brief Cover Letter outlining your experience and interest in the role.

If you enjoy enterprise software, complex business systems, integration challenges and helping evolve established software platforms, we'd love to hear from you.

QUALIFICATION QUESTIONS (please include in cover letter)

1. 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 • 12-15 years • 15+ years
2. 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
3. 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
4. Have you been involved in maintaining, modernising or evolving a legacy software platform? • No • Minor contribution • Significant contributor • Led major components
5. 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
6. What is your level of experience designing and implementing APIs and software integrations? • None • Basic • Intermediate • Advanced • Expert
7. 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
8. Which accounting or ERP platforms have you integrated with? • MYOB Exo • MYOB Advanced • Xero • SAP • Dynamics • NetSuite • Pronto • TechnologyOne • Other • None
9. 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
10. What interests you most about this role?

Bonus Question (Highly Recommended)

1. 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?