Senior Software Engineer

FairSupply; Sydney; On-site; AUD 150,000 - 190,000; Full time

Job summary

FairSupply, a Sydney-based startup, seeks a Senior Software Engineer to own complex, data-heavy features across our Next.js/TypeScript stack and the data layer that powers it. You’ll take problems from scoping to production, shaping architecture and trade-offs, and delivering reliable, auditable results at scale.

You’ll work with AI tooling, run production-grade code, and influence platform evolution in a small, autonomous team.

Job description

Sydney-based. Melbourne candidates are welcome to apply.

Picture this. A customer hands you a year of procurement spend. Tens of thousands of rows, misspelt supplier names, inconsistent categories, several currencies. It needs to be processed in real time from a number of internal database calculations spanning hundreds of thousands of datapoints, combined with agentic AI workloads researching and ingesting pages and pages of relevant data autonomously and delivered to the user in seconds or minutes into an industry leading product experience that makes the complexity of all of this seem simple to anyone.

That's a normal day here.

Why this isn't another SaaS developer job

Most SaaS is a thin layer of interface over a database, and that's exactly the kind of software AI is commoditising fastest. Fair Supply is the opposite, the data layer is the product. Under the hood is our supply chain mapping engine, which models how money, emissions and risk flow between industries and countries across the global economy. On top of it sits classification, risk modelling and audit-grade reporting that some of Australia's most regulated companies rely on for their climate (AASB S2) and modern slavery disclosures.

The hard problems aren't the screens. They're resolving and classifying messy company data at scale, modelling supply chains you can't directly see, and making every output explainable enough to stand up to an auditor.

This role is for someone who simply loves building things, and still gets a kick out of shipping something hard and seeing it work. You'll spend your days hands‑on, designing, coding and solving problems, not managing people or sitting in meetings. This isn't a stepping stone to an engineering manager or CTO, and that's deliberate. Growth here means bigger problems, more ownership and more technical influence over time, along a senior IC path toward Lead or Principal.

That's what AI-first development makes possible. One great senior engineer working with modern AI tooling can now have the kind of impact that used to take a small team. We want people who are energised by that, not people looking for a team to run.

About this opportunity

We're a startup with a small engineering team with blue‑chip customers who renew because regulation now requires them to answer questions that they don’t have answers for. That means real demand, real data, and real consequences for getting it right.

As our Senior Software Engineer, you'll own complex, data‑heavy features end to end, across our Next.js/TypeScript stack and down into the data that powers it. You'll take problems from rough idea to production, shaping the technical approach, making the calls on architecture and trade‑offs, and standing behind the quality of what ships. In a team this size, your technical judgement shapes how the platform evolves, not just the features you build.

We build AI-first, on a modern stack

That starts with how we work: AI coding agents, custom harnesses and eval and QA tooling are part of how we write, review and ship code every day, and if you'd be happy to never go back to writing code by hand, you'll fit right in. But it goes well beyond coding. Our platform runs on the kind of stack most engineers only read about:

• Graph databases modelling global supply chains
• Agentic workflows running in production
• AI evals and tracing to keep model outputs measurable and trustworthy
• Structured data models that turn unstructured inputs into audit‑grade results

You don't need to have used all of it. You do need to be the kind of engineer who wants to.

You don't need an ESG background either. You need to love hard problems, care about the quality of your work, and be unfazed by complex data.

What you'll do

• Own complex, data‑heavy features end to end: take problems from scoping to production across our Next.js/TypeScript stack and the data layer underneath it, and own how they perform once they're live.
• Build AI-first, every day: use AI coding agents as your default way of designing, writing, testing and shipping code, and help us keep evolving how we use them.
• Get under the hood: develop a deep understanding of our data model, emissions engine and classification pipelines, so knowledge of how the platform really works is shared, not held by a few.
• Stand behind your work: test your own code and take accountability for quality and outcomes in production.
• Work across disciplines: collaborate with design, data and product to shape what we build, not just how we build it.
• Be a trusted technical voice: work alongside our technical leads as a peer, with the judgement and code quality the team can rely on, and help shape how we build software as we grow.

You'll love this if you…

• Love building: you get your energy from solving hard problems and shipping great work, not from titles or managing people.
• Already work AI-first: AI coding tools are part of how you work every day, not something you've tried once, and you're excited about where this is heading.
• Have gone deeper than CRUD: you've worked on a data‑heavy platform with real complexity under the hood.
• Own the whole job: you've built and run production software end to end, including testing, quality and outcomes.
• Know the full stack: you're a senior engineer (typically 5+ years) who's strong across Next.js, TypeScript and modern web tooling.
• Have done the startup thing: you've worked somewhere early‑stage, built things from scratch and found your way through ambiguity without a playbook.
• Write clearly: you communicate well, especially in writing, which matters in a hybrid team.
• Take change in your stride: our tools, systems and strategy are still evolving, and that energises you rather than unsettles you.

Bonus points if you've worked with graph databases. No ESG background needed; you'll pick up the domain here.

What working here feels like

You'll join a team that's figured out how to be deeply ambitious about the work while staying genuinely kind to each other. People here want to do great work, but egos don't run the show. When someone hits a rough patch, colleagues show up to help.

You get real autonomy to make decisions and own your work. No micromanaging, no endless approval chains. Leadership keeps everyone in the loop about what's happening, both the good news and the challenging stuff.

The work is hard, and it matters. Our customers rely on what we build to answer the questions their boards and regulators are asking about emissions, modern slavery and nature. Getting those answers right is a serious technical challenge, and it makes a measurable difference.

We're not perfect. We're still building and figuring things out as we go. But we've got clear focus, customers who love what we've built, and the kind of momentum that makes you excited about what's possible. Plus, people here know how to celebrate wins together and laugh when things get messy, which they inevitably do.

Ready to build something hard?

This is your chance to join a small team solving hard data problems at exactly the right moment. You'll work hands‑on with modern tools, alongside smart, kind people, and help build the global standard for supply chain transparency.

If you've read this far thinking "this sounds like the challenge I've been waiting for", let's talk.

We'd love to meet you.