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Senior Full Stack Engineer - AI Harness

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The Role

The role / impact

This senior engineering position owns a critical delivery stream on MyXero, the foundational platform that underpins every organisation and user record while managing hundreds of millions of daily requests. You will take ambiguous platform challenges from problem framing to durable architectural solutions, designing the specs, verification harnesses, and AI guardrails that enable software agents to handle implementation safely.

Your work directly enables the modernisation of a massive system into decoupled domain services without disrupting dependent products. By engineering automated verification loops and robust testing harnesses, you will ensure high reliability, mentor team members, and shape how our engineering practices operate safely with intelligent tools.

The team / how they connect

You will join the MyXero Ghostbusters squad within our Identity and Platform group, collaborating with engineers and product partners primarily based across New Zealand. The team operates with a written-first, remote-first philosophy, using design records, paired kick-offs, and blameless reviews to ensure every voice is heard and no one works in isolation. While delivery is high-tempo, the group maintains a supportive, open environment where technical curiosity and shared learning are core to daily routines.

Initially, you will focus on

  • Setting up an intentional local development harness with automated validation checks to safely handle production changes.

  • Refactoring legacy monolith endpoints and services built on .NET Framework, C#, and SQL Server towards modern APIs.

  • Developing automated verification loops, test simulation harnesses, and tools that reduce operational toil and human checks.

  • Building cloud agent tooling and collaborative workflows that support the evolution toward an automated development lifecycle.

Where and how you can work

This role is open to candidates based in New Zealand, offering a flexible remote-first setup with office access in Wellington or Auckland. Our working environment is structured around async communication and balanced collaboration.

Here are some of the things we are looking for

  • You bring deep full-stack or backend engineering experience with typed languages, ideally with exposure to C# and .NET environments.

  • Hands-on exploration with AI harnesses, coding agents, or automated verification pipelines in a personal or professional setting.

  • Practical familiarity with distributed systems architecture, API design, data modeling, and managing complex relational database migrations.

  • Proven capability in taking ambiguous technical problems from initial conception to production delivery.

  • Strong written communication skills to articulate system trade-offs clearly through design records and technical documentation.

  • A collaborative mindset with a drive to share learnings, uplift team capabilities, and contribute constructively to production support rotations.

Apply even if your experience isn't a perfect match! At Xero, we hire based on your skills, passion, and the unique perspective you can bring to enhance our culture and team.

Senior Full Stack Engineer - AI Harness

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Melbourne

Xero’s head office in Australia is in the buzzing suburb of Hawthorn, a stone’s throw from the CBD. Here, a diverse mix of Xeros work in both global and regional teams.

Brisbane

Our beautiful sunlit office is close to Brisbane Central Train Station and walking distance from Queen Street Mall as well as King George Square.

Sydney

Our office is in the heart of the Sydney CBD with views of the Sydney Harbour Bridge. We're just over by Wynyard Park so it's easy to get to.

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Toronto

Our Canadian office is located in the heart of Toronto and has the city’s financial district at its doorstep.

Calgary

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New Zealand

Aotearoa New Zealand is our birthplace and where our work is anchored in three foundational themes reflecting both our heritage and our global ambition: Pioneering Innovation, Kiwi Roots, Globally Driven, and Community at our Core.

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Wellington (HQ - Xero One)

Our home base. We’ve got a world-class office space with almost every part of the business having a team here.

Auckland

Our Auckland employees are based in a bright, modern building in Parnell. Te Ara Turoa means ‘the journey of enduring light’, which refers to the history and significance of the land where the building stands.

Napier, Hawke's Bay

A converted old wool-store is where you'll find our Hawke’s Bay office. It’s a sunny base for our customer support crew and other teams.

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Singapore

Located in the heart of Singapore, our office is the headquarters for the South East Asia region.

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South Africa

Our Cape Town office is Xero's base in South Africa, and Johannesburg is home to the Syft team. In South Africa, we have a history of being first to market with ground-breaking features that solve real problems for accountants, bookkeepers and small businesses. We're proud to have built a thriving community in South Africa for 10+ years.

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Cape Town

Our South African office is located in Cape Town. It's a brand new office space just a stone’s throw from a collection of coffee shops, restaurants, and shops.

Johannesburg

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Milton Keynes (HQ + Experience Center)

This vibrant office is our welcoming UK headquarters. It’s close to the train station as well as cycling and walking paths.

London

The office is a 2 minute walk from the station - Exit Liverpool Street Station from the Bishopsgate exit, cross at the traffic lights and turn left onto New Street and follow the road.

Manchester

At the center of Manchester’s thriving tech hub and business district, this UK office is surrounded by creativity and innovation.

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Denver

Headquarters for the Americas, the sleek and modern Denver office is in the heart of the Platte Street area and right near the scenic Platte River.

New York

Xero’s (and Melio's) office is conveniently located in midtown Manhattan.

San Mateo

Our Bay Area office located in San Mateo features collaborative and transformative spaces perfect for team gatherings.

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Welcome to life inside Xero — where we're building the future of small business around the world.

No matter where you join us from, you’ll find a team that balances global impact and high performance with genuine flexibility, ensuring you have the space to be your best and supercharge your career.

Step into our world

How we hire

We know interviews can be a bit nerve-wracking. So we've laid out what to expect, how to prepare, and what to expect through the process. 

Connect with our talent team

You’ll connect with our talent team for the initial screen via Google Meet. This call will go over your background, experience, and career goals, as well as what to expect in the process and any questions you may have. We’re focused on finding folks who not only have the right skills, but also align with our values and dynamic way of working.

Show us your skills

In this interview(s) we want to learn more about your job skills and domain expertise. Anticipate a case study, a tech exercise, a portfolio review, and/or time with your team to dive into role related activities. Don't worry, no matter the role we'll make sure you're prepared to put your best foot forward!

Values in action

We want to hear how you demonstrate and connect with our values and the future of work at Xero. Be prepared to share examples of how you drive results and work cross-functionally and focus on the “customer”. You’ll be meeting with your potential new team so it’s a great opportunity to ask any questions you may have, too. Go Bold. Go Fast. Go Further. Go Together.

LEADership Interview (people leaders only)

For people leaders, our interviews focus on our four LEAD principles: 1) Lead with vision 2) Elevate capability 3) Act like an owner 4) Distill and solve problems

Decision and offer

Once you've connected with the team and manager, and everyone (including you!) agree we've found the best fit, we'll move to offer.

Supporting Xeros to thrive

From flexible working and wellbeing support to professional growth and meaningful perks, we help you do your best work, and feel great doing it.

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Leave

Annual leave: 20+ days a year

Wellbeing leave: 10+ days a year, pro-rated based on start date

Xtra leave: Five days a year to use whenever and however

Parental leave: 26 weeks paid leave with top-ups, up to 100%, Partner leave: 6 weeks paid leave in baby’s first year

Holiday leave: Three extra days over year-end shutdown (it's on the house!)

Lifestyle leave: Purchase additional time off, spread the cost over the year

Community Connect: One paid day per year for volunteering

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Wellbeing

Flexible working is not just a nice to have at Xero, itʼs the way we do things.

Employee Assistance Programs (EAP): Access free, confidential support for you and your family as part of our wellbeing program.

Modern Health: A free benefit, and our global EAP, for Xero employees and immediate family members to support and promote the wellbeing of Xeros and their families as part of our global wellbeing strategy. This service includes six coaching and six counselling sessions plus access to unique work life services that are available globally.

Mentorloop: Every Xero has access to Mentorloop, our platform for finding a mentor.

Local wellbeing programs: New wellbeing programs and activities are offered regularly in each region.

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Rewards

Employee Share Plan (ESP): Own a small portion of Xero through the employee share plan (ESP). Each year, every Xero receives a percentage of their base salary in Xero shares. The number of shares varies yearly based on salary and share price. Shares are typically offered in July and, for new employees, they’re pro-rated depending on start date.

Medical insurance: Xeros in all regions can expect exceptional medical insurance coverage provided by Xero. Many regions even have a fully subsidised option for eligible Xeros.

Retirement: Competitive retirement plan options with a matching contribution from Xero.

Life insurance: Life insurance coverage is provided to Xeros with a minimum coverage amount equivalent to their base annual salary.

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Xero

Xero subscription: Use our beautiful easy-to-use accounting software for your side gig or personal finances.

Xero rewards: Gain access to an array of retail discounts including stores, restaurants, holidays and products.

Global impact: Work for a company that’s in 9 countries and has 23 offices.

Environmentally conscious: Xero is certified carbon neutral and committed to supporting our customers, partners and their communities to become more sustainable.

Not ready to join us just yet?

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