Senior Software Engineer (Contractor)

About Casu

Casu is a platform that connects businesses with casual workers, enabling flexible, casual employment through a single system.

Beyond matching businesses and workers via the Casu app, the platform manages the full employment process end-to-end, including onboarding, timesheets, and payroll.

Casu operates as a Digital Service Provider with the ATO, integrating with systems such as Single Touch (STP) and Ozedi.

It is a live platform used by businesses and workers across Queensland and New South Wales, where system reliability and accuracy are critical.

The Role

Senior Software Engineer engaged as a contractor to deliver and contribute to defined engineering outcomes across the Casu platform.

This is a hands-on role focused on building, improving, and maintaining key parts of the system. Work is prioritised to a small number of high-impact areas at any given time.

Key Responsibilities

• Develop and maintain backend services (Node.js) and mobile applications
• Build and support integrations with external systems (e.g. Single Touch, Ozedi)
• Review and improve code quality, including AI-assisted code
• Develop and maintain test coverage
• Contribute to system reliability, performance, and maintainability
• Document systems, code, and key technical decisions
• Support defined technical initiatives and product improvements

Tech Stack

App: Flutter (Dart) - iOS, Android, Web, plus internal admin/CRM tools

Backend: Firebase Cloud Functions (Node.js)

Database: Firestore (NoSQL)

Infrastructure: GCP, Firebase, Cloud Run, Cloud Storage

Integrations: Stripe, Ozedi (SuperStream), Single Touch Payroll (STP), Twilio, Slack, Gmail, Meta

Essential Skills

We are looking for an experienced full-stack engineer with strong fundamentals and experience owning products end-to-end. Experience across all listed technologies is not required.

• Hands-on software development experience with JavaScript backend (Node.js)
• Hands-on experience building cross-platform applications (Flutter, React Native, or similar)
• Hands-on experience working with AI development tools / agents (e.g. Claude, Cursor or similar)
• Strong code review experience (both human-written and AI-generated code)
• Experience with test case development
• Ability to understand requirements, prioritise work, and translate into execution.

Preferred Skills

• Flutter
• Firebase / Google Cloud
• Experience in startup or early-stage environments
• People management or mentoring experience
• Consideration of cloud and infrastructure costs in technical decisions
• Exposure to business and technology strategy

Engagement Details

• Independent contractor engagement
• ~20 hours per week
• Monthly budget: ~$10,000
• Availability required on Mondays
• Remaining hours flexible within standard business hours
• Opportunity to increase hours over time based on business needs and performance.

Location

• Fully remote
• Brisbane-based candidates preferred
• Periodic in-person collaboration required

Role Context

Casu sits at the intersection of:

• a two-sided marketplace (businesses and workers)
• a mobile and backend product
• a compliance and payroll system

The platform requires handling real-time job matching, payroll accuracy, and regulatory compliance across a growing user base.