Senior Software Engineer - Python

Senior Backend Engineer (Python & AWS) North Sydney | Hybrid (3 days in office)

This isn’t a role for someone who just wants to ship tickets.

It’s for an engineer who wants to shape architecture, modernise a real platform, and influence technical direction inside a profitable, globally operating data business.

The company operates at serious scale, processing and resolving large volumes of identity and data signals used by major international organisations. They are stable, growing (40%+ revenue growth over the past two years), and backed by long-term enterprise contracts.

Now they’re ready to uplift their platform for its next phase.

What You’ll Love About Working Here

1. Genuine Architectural Influence: You’ll act as a 2IC to the Head of Technology. Your thinking will shape direction not just implementation.

2. Real Scale (Not Resume Scale): Large datasets. Performance-sensitive systems. Complex resolution logic. You’ll solve meaningful engineering problems, not UI tweaks.

3. Modernisation with Backing: There’s technical debt and full leadership buy-in to fix it properly.

4. Stability Without Bureaucracy: Profitable. Long-tenured team. Flat structure. No corporate red tape but strong standards and ISO discipline.

5. Ownership Over Noise: You won’t be one of 200 engineers. You’ll be one of a small, high-trust team.

What You’ll Get From This Role

End-to-end ownership of backend architecture decisions

Exposure to large-scale AWS system design

The opportunity to uplift engineering standards

Influence over roadmap and prioritisation

A stable environment where your work compounds over time

If you want to look back in three years and say, “I built that platform properly” - this is that role.

What You Need to Have Already Done

6–10 years backend engineering experience

Designed and built production systems in AWS

Strong Python expertise (Django/Flask or similar)

Worked on systems handling meaningful data scale

Made architectural decisions not just implemented them

Improved performance, security, or scalability of legacy systems

Influenced stakeholders and extracted unclear requirements

You must be able to

Think architecturally first

Communicate with gravitas

Operate without ego in a flat structure

Prioritise effectively when everything feels important

Environment

AWS cloud-native

Python backend

Snowflake and large-scale data querying

Hybrid (Mon, Tues, Fri in North Sydney - weekly team lunches)

Strong culture, many team members have worked together 10-15+ years

Investment in learning and conferences

This role suits someone who wants impact over title. Ownership over hierarchy. And long-term influence over short-term noise.

If this sounds like you then apply here or share your resume to Dani – danielle@theonset.com.au

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