Senior/Lead - AI Systems Engineer (RoR)

Melbourne CBD

$180-$240k + Super + Bonus A fast-growing fintech in the invoice payments space, building the tooling that lets its engineers develop production software alongside AI coding agents. It's an early, high-trust environment for this kind of work: the harness you build becomes the way the whole engineering team ships. Strong investment in tooling, a social culture, and genuine scope to shape how AI-native development gets done here.

Role and responsibilities

You'll own the tooling layer that sits between engineers and the AI coding agents they build with. That means building and maintaining the coding agent harness itself: MCP servers, tooling, integrations, conventions and workflows. You'll partner with product, design and engineering to ship production software using AI-native practices, and prepare the core codebase for agent-authored change with clear module boundaries and robust test coverage.

You'll also prove the harness works. That's evaluation frameworks and feedback loops to measure agent performance and workflow effectiveness, investigating failures, and feeding fixes back into the system. On the reliability side, you'll build and maintain the security, privacy and guardrail controls that stop unsafe or unauthorised agent use, plus the automated checks and rollback paths that protect critical flows when something goes wrong.





When incidents happen, you'll be the one triaging, recovering and writing up root cause.

Beyond your own build, you'll make the harness easy for other teams to adopt: reusable tooling, documentation, and hands-on support for teams using the coding agent day to day.

Key technical skills

- 5+ years of software engineering experience, with real time shipping and supporting production systems
- Strong Ruby on Rails and PostgreSQL, this is a Rails-first codebase and the agents ship straight into it
- Hands-on experience using AI coding agents in a real codebase, with a clear view of where they help and where they don't
- Experience building developer tooling, internal platforms or developer experience work other engineers relied on
- Practical experience with MCP servers, tool integrations or comparable agent tooling
- Solid AWS experience and comfort with Terraform
- Comfortable with release, rollback and change control where mistakes carry real business consequences
- Direct experience investigating failures: triage, containment, recovery and root cause write-ups
- Financial services or another reliability-critical domain is a bonus, as is DDD exposure

Location and package Melbourne CBD. Hybrid, Tuesday to Thursday in office, WFH Monday and Friday (3 days in office).

📌 Senior/Lead AI Engineer (Melbourne)
🏢 Preacta
📍 Melbourne