Senior Full Stack .NET Developer - Enterprise Applications & Integrations

Existco PTY LTD; Perth; On-site; AUD 100,000 - 120,000; Full time

Job summary

Existco PTY LTD in Australia seeks a Senior Full Stack .NET Developer to evolve ExPCS, our plant control and ERP platform used by manufacturing, distribution and logistics customers internationally.

You will maintain VB.NET/WinForms code while designing APIs and backend services for an API-first ecosystem across web, mobile, cloud and desktop.

Collaborating with stakeholders and ensuring seamless ERP and accounting integrations, you will help shape the platform's future direction.

Qualifications

• 8+ years commercial software development experience.
• Strong C# and .NET capability.
• Experience designing and implementing REST APIs.
• Experience integrating software with external systems.
• Excellent collaboration and communication skills.

Responsibilities

• Maintain, enhance and support the 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 modernization of legacy applications and services.
• Collaborate on architecture, platform improvements and future product direction.
• Troubleshoot and resolve complex technical challenges.

Skills

C#

VB.NET

WinForms

REST APIs

Azure

SQL Server

TypeScript

Tools

Visual Studio

Azure DevOps

Job description

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

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 12-15 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?

ExPCS - Existco Plant Control System 7 subscribers