Senior Software Engineer - Financial Operations team Add expected salary to your profile for insights
At Fat Zebra, w e simplify payments so merchants and platforms can scale with confidence. Our flexible, secure, and scalable payments platform supports over100,000 merchantsacross Australiaand New Zealand, helping them navigate the complexity of the payments ecosystem so they can focus on what matters most — growing their business.
About the Role:
We’re looking for a Senior Software Engineer to join our Financial Operations team. We are responsible for building and maintaining the systems that power Fat Zebra’s settlements, billing, and treasury. Our work directly supports Fat Zebra’s merchants by ensuring timely and accurate settlement of funds, clear and consistent transaction reporting, and the real-time pricing of transactions. These outcomes are critical to our merchants' financial visibility and trust in our platform.
At Fat Zebra, we build and maintain a blend of monoliths and service-oriented systems. Much of our architecture is event-driven, reflecting the asynchronous nature of real-world payments and settlements. This team ensures the secure, accurate, and scalable handling of large transaction volumes across payment networks, internal ledgers, and banking partners.
You’ll be joining a team of senior engineers that thrives on solving hard problems in distributed systems, data integrity, and financial correctness. Our tech stack is primarily Ruby on Rails, alongside TypeScript, React, Postgres, AWS, and Terraform. This role does involve some full‑stack exposure but is primarily backend‑focused. We value simplicity, strong interfaces, and observability and we continuously refine our systems to be more robust and scalable as we grow.
Key Responsibilities:
Design and build backend services that power settlements, billing, and treasury.
Deliver services that focus on security, scalability, reliability, observability, and regulatory compliance.
Participate in the full development lifecycle, from architecture and design through implementation, testing, deployment, and ongoing operations.
Write well‑tested, maintainable code that supports long‑term system health and developer productivity.
Diagnose and resolve issues across services, contributing to incident response and support.
Document and share knowledge to help others navigate the complexity of our payment ecosystem.
Collaborate across teams, working closely with engineers, product managers, and partners to shape product direction, define requirements, and deliver solutions.
About You:
You have 5+ years of hands‑on experience as a software engineer, ideally building and maintaining backend services in a production environment.
Comfortable working with one or more of our core technologies, especially Ruby and Ruby on Rails.
You’re confident picking up new languages and tools as needed.
You have a strong foundation in software engineering principles, writing maintainable code, designing clean interfaces, building systems that are observable, testable, and resilient.
Familiar with event‑driven architecture, service‑oriented systems and understand the trade‑offs between working with distributed components and shared state.
You’re at ease navigating complexity, whether it’s mapping out payment flows across multiple services, reasoning about concurrency and edge cases, or handling regulatory constraints with care.
You take ownership of your work, follow through on commitments, and actively contribute to a culture of reliability, safety, and continuous improvement.
Flexible hybrid working arrangements and a supportive, people‑first culture.
You must have working rights in Australia to apply for this role.
You must complete an appropriate background check relevant to the role.
We do not accept candidates from outside Australia for this role.
For a confidential discussion please contact Fat Zebra’s
Talent Manager Rose Filippone on
Your application will include the following questions:
Are you on any kind of visa (temporary or permanent)? If so, please indicate what visa you are on and any working restrictions that may apply.
What is your current notice period (in weeks)? The position requires a minimum of 3 days in the office. Are you comfortable with this working arrangement?
How many years of production Ruby experience do you have?
Can you describe a large‑scale distributed system you architected or led, including the key design decisions you made, how you balanced short‑term delivery with long‑term maintainability, and what trade‑offs you had to manage?
Give an example of how you've designed or improved observability for a complex system — what tools or approaches you used for logging, metrics, tracing, dashboards, and alerting, and how it improved reliability or incident response.
Can you walk us through a time you noticed a potential risk or inefficiency in a financial or transactional system (e.g. settlements, reconciliation, pricing, or reporting), asked deeper questions to understand the root cause, and then delivered a solution? What questions did you ask, and what was the impact on accuracy, customer trust, or operational efficiency?
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