Senior Software Engineer

REX SOFTWARE GROUP
Senior Position Description
AI Native Senior Software Engineer
Reports to

Head of Engineering (or relevant Tech Lead)
Direct Reports

None (informal technical mentoring across the product stream and wider engineering team)
Location

Australia-based (East coast preferred / Remote AU)
Scope

Product stream technical leadership, with cross-stream influence on AI-native standards and practices
Domain

AI-native software development, AI agent orchestration, and product delivery
Role Overview

Rex Software Group is transitioning to an AI-native operating model. This is not about adding AI features to a traditional development process, it is a fundamental shift in how we build and ship software. Our target is Level 4 AI maturity: humans define the architecture, usage scenarios, and acceptance criteria, while AI agents autonomously write, review, and fix code.

The AI Native Senior Software Engineer is a senior engineering role for builders who already work this way and can set the standard for others to follow. You will be embedded within a product stream (Rex CRM or Rex PM) as its most experienced AI-native practitioner, expected to deliver production-quality software using AI coding agents as your primary development tool, and expected to shape how the rest of the stream, and over time the wider engineering organisation, works with AI agents.

You are not writing every line of code by hand, you are orchestrating AI agents to do it, auditing their output, and ensuring the result meets the architectural and quality standards of the codebase. This is explicitly not a “vibe-coding” role. At senior level, you also carry accountability for the technical decisions and AI-native practices of your stream, not just your own output.

This role requires a different profile to a traditional senior software engineer. You must have the engineering maturity to recognise when AI-generated code is correct, performant, and secure, and the judgement to know when it is not, at a level that lets you set standards others follow. You must be comfortable providing constructive, architectural feedback to AI tools the same way a senior engineer coaches a junior developer, with patience, precision, and clear expectations, and you must be equally comfortable coaching human engineers in how to do the same.
Key Responsibilities

AI-Native Product Development & Technical Leadership

- Deliver production-quality features and fixes within your assigned product stream using AI coding agents as the primary development tool, taking on the most architecturally significant or ambiguous work in the stream

- Set the technical direction for how AI agents are orchestrated within your stream, including standards for prompting, context management, and agent-generated code review

- Critically audit AI-generated code for correctness, performance, security, and adherence to Rex's coding standards, and coach other engineers to do the same

- Own and continuously improve the prompts, context documents, and system instructions (AGENTS.md, Skills, and related documentation) that train AI agents on Rex's architecture, patterns, and conventions for your stream

- Identify tasks best suited for AI-assisted development versus manual implementation, and help other engineers build this judgment

- Make or strongly influence build-vs-buy and architectural trade-off decisions within your product stream

Engineering Quality & Architecture

- Own the system architecture within your stream, including database schemas, API contracts, service boundaries, and deployment pipelines, and ensure AI-native workflows respect and reinforce that architecture

- Lead technical design discussions, code reviews, and architectural decisions within your product stream, and act as an escalation point for complex technical judgement calls

- Set and maintain test coverage standards, ensuring AI-generated code is consistently accompanied by appropriate automated tests across the