Senior Full-Stack Developer

18th September, 2026

A leading R&D company based in Castle Hill are currently seeking a full-stack developer to join their growing engineering team.
You'll be working within a technically strong R&D environment, developing and supporting software used across the company's products and systems.
The role will involve a mix of front-end and back-end development, working closely with a small team of fullstack devs and AI developers to build reliable, user-friendly applications.
The company are looking for an engineer that's interested in real-world technology and product development, rather than purely web-based projects.
This is a full-time, permanent position which requires you to be onsite in the Castle Hill office.
You must have working rights in Australia to be eligible for this position.
Key Requirements:
Backend Development:

API Development & Architecture

• Design, implement, and maintain RESTful APIs using NestJS, with full OpenAPI/Swagger documentation.
• Implement secure JWT-based authentication with access/refresh tokens using HTTP-only cookies.
• Define and validate DTOs with NestJS validation pipes for type-safe request/response contracts.
• Configure CORS policies, rate limiting (e.g., 40 requests/min/user), and comprehensive request logging.
• Maintain backward-compatible API versioning, planning for future iterations.

Asynchronous Processing & Job Queues

• Architect and maintain BullMQ queues for background job processing.
• Handle long-running tasks (e.g., floor plan analysis, ML API integration) with retry and exponential backoff strategies.
• Monitor queue health, optimise concurrency, and scale processing capacity efficiently.

Database Design & Optimisation

• Design normalised PostgreSQL schemas with proper relationships, constraints, and indexing.
• Use TypeORM for entities, migrations, and data integrity management.
• Optimise queries to prevent N+1 issues and ensure sub-second response times.
• Implement transactional consistency for critical multi-step operations.
• Work with Google Cloud SQL for high availability, backups, and disaster recovery.

Cloud & Infrastructure Integration

• Integrate with Google Cloud Storage for secure file handling.
• Manage Redis connections for BullMQ job persistence.
• Design event-driven systems using Google Cloud Pub/Sub; implement publish-subscribe patterns, versioned message schemas, and dead-letter handling.
• Ensure reliable message delivery (exactly-once / at-least-once semantics) and monitor system metrics.
• Deploy containerised microservices on Google Cloud Run with auto-scaling, health checks, and zero-downtime updates.
• Build serverless functions (GCF Gen 2) triggered by HTTP, Pub/Sub, Firestore, or Storage events with proper retry, idempotency, and performance optimisation.

Highly Desirable Skills:

• Build responsive, TypeScript-based React.js applications.
• Good knowledge using Javascript
• Develop reusable UI components, manage state (Redux, Zustand, or Context API), and integrate backend APIs efficiently.
• Implement real-time updates with WebSockets for job tracking and notifications.
• Collaborate with designers to create pixel-perfect, accessible interfaces using Tailwind CSS and shadcn/ui.
• Optimise performance: code splitting, lazy loading, and bundle size reduction.
• Implement form validation with React Hook Form and Zod, and efficient server state management via React Query.
• Build interactive data visualisations for analytics and reporting
• Experience working with machine learning and AI

This role is fully onsite in Castle Hill and requires you to already hold a valid working visa in Australia. Sponsorship is not provided.
Codematix is a recruitment agency. You can find out more about Codematix by visiting