# Principal Engineer - Payments Products & Platform
**Company:** [Xero](https://scaleengineer.com/companies/xero)
Principal Engineer leading payments strategy across Xero's dual portfolio of Payments Products & Experiences and Payments Platform, architecting systems handling billions in daily transactions across 150,000+ daily payments. This role combines hands-on technical leadership with strategic influence over 40-50 engineers, requiring deep expertise in distributed systems, API-first architecture, cloud infrastructure, and fintech domain knowledge to design scalable, resilient payment systems.
**Role:** Principal Engineer
**Seniority:** Principal
**Locations:** AU: Sydney (45 Clarence St)
**Salary:** 180000–250000 AUD
[Apply](https://jobs.ashbyhq.com/xero/0950bd50-2ea2-41c3-8bba-4afd9cf060d6)
Canonical: https://scaleengineer.com/jobs/xero/principal-engineer-payments-products-platform
---
## Requirements

### education

- {"name":"Computer Science or Related Field","description":"Formal education in computer science, software engineering, or related discipline providing theoretical foundations in distributed systems, algorithms, and data structures. Equivalent professional experience strongly considered."}

### technical

- {"name":"Large-Scale Distributed Systems","description":"Design, implementation, and operation of production distributed systems balancing reliability, performance, and cost. Demonstrated ability handling high transaction volumes and managing system complexity at billion-dollar daily throughput."}
- {"name":"Microservices Architecture","description":"Deep expertise building and maintaining microservices spanning web, API, and data layers with clear service boundaries, communication patterns, and operational strategies."}
- {"name":"API-First Design Thinking","description":"Architecting systems from API contracts outward, ensuring product-agnostic interfaces that multiple teams consume. Ability to evolve APIs while maintaining backward compatibility and supporting innovation."}
- {"name":"Backend Language Proficiency","description":"Fluent production experience with at least one modern backend language (C#, Java, Go, C++), making informed technology choices aligned with architectural requirements and team capabilities."}
- {"name":"SQL & NoSQL Databases","description":"Advanced experience designing schemas, optimizing queries, managing transactions, and selecting appropriate data stores for different payment system requirements. Understanding of ledger systems and financial data integrity."}
- {"name":"Cloud-Native Platforms","description":"Hands-on AWS expertise including compute, managed services, networking, storage, and cost optimization. Understanding of deploying microservices at scale with high availability and disaster recovery."}
- {"name":"Legacy System Analysis & Modernization","description":"Ability to pragmatically assess existing systems and make data-driven decisions on extending, migrating, or rebuilding. Experience managing technical debt and executing incremental migrations with minimal business disruption."}
- {"name":"AI Tooling Integration","description":"Strong interest and practical experience integrating AI tools into engineering workflows and products. Demonstrated ability modeling AI adoption to improve productivity and product capabilities."}

### experience

- {"name":"Principal or Staff Engineer Role","description":"Minimum 12-15 years of software engineering experience with 3-5 years at staff or principal level. Demonstrated progression through IC roles with increasing scope, complexity, and organizational impact."}
- {"name":"Payments or Fintech Domain","description":"3+ years working in payments, fintech, or similar high-stakes financial systems where reliability, consistency, and compliance are critical. Understanding of payment flows, settlement, reconciliation, and regulatory requirements."}
- {"name":"Large-Scale System Architecture","description":"Proven experience architecting systems handling billions of daily transactions or equivalent scale. Demonstrated ability designing for reliability at scale with 99.9%+ uptime requirements."}
- {"name":"Technical Leadership & Influence","description":"Track record of shaping technical direction across multiple teams without formal authority. Evidence of mentoring senior engineers, establishing engineering standards, and driving adoption of best practices."}
- {"name":"Multi-Team Collaboration","description":"Experience partnering with product, design, and business stakeholders to translate complex requirements into scalable technical solutions. Demonstrated ability to communicate technical concepts to non-technical audiences."}

## Skills

### required

- {"name":"Distributed Systems Design","description":"Proven expertise designing and operating large-scale distributed systems in production environments, managing trade-offs between reliability, performance, scalability, and operational cost. Experience architecting systems handling high transaction volumes and complex state management across multiple services."}
- {"name":"API-First Architecture","description":"Deep proficiency designing product-agnostic APIs that serve multiple consumer teams and platforms. Experience building RESTful or event-driven architectures, API versioning strategies, and ensuring API contracts maintain backward compatibility while supporting innovation."}
- {"name":"Backend Languages","description":"Fluency in at least one modern backend language such as C#, Java, Go, or C++. Demonstrated ability to make informed technology choices based on performance requirements, team expertise, and architectural constraints specific to payments and fintech systems."}
- {"name":"Database Design","description":"Strong experience with both SQL and NoSQL data stores, including schema design for high-throughput systems, query optimization, transaction consistency models (ACID, eventual consistency), and data migration strategies. Understanding of ledger systems and financial data integrity requirements."}
- {"name":"Cloud Infrastructure","description":"Hands-on expertise with AWS cloud-native platforms, including compute services, managed databases, messaging, and monitoring. Experience designing cost-effective architectures at scale and managing multi-environment deployments with infrastructure-as-code principles."}
- {"name":"Payments & Fintech Domain Knowledge","description":"Deep understanding of payment systems architecture, payment flows, regulatory compliance, reconciliation processes, and settlement mechanics. Experience working with payment processors, gateway integrations, and understanding of financial risk management."}
- {"name":"Technical Leadership & Mentorship","description":"Demonstrated ability to mentor senior and staff engineers, shape architectural decisions through influence rather than authority, and set engineering standards across distributed teams. Evidence of driving cross-functional technical initiatives and raising engineering practice organization-wide."}
- {"name":"Legacy System Modernization","description":"Proven track record making pragmatic decisions on which legacy systems to extend, migrate, or rebuild. Experience managing technical debt, executing incremental migrations, and balancing greenfield innovation with brownfield maintenance."}
- {"name":"AI/ML Integration","description":"Strong interest and demonstrated capability in evaluating and integrating AI tooling into engineering workflows and product features. Experience using AI for task automation, code generation, and improving engineering productivity and outcomes."}

### preferred

- {"name":"Microservices Architecture","description":"Extensive experience designing, implementing, and operating microservices architectures in production, including service boundaries, inter-service communication patterns, observability, and deployment strategies."}
- {"name":"Growth Analytics & A/B Testing","description":"Hands-on experience designing and analyzing A/B tests that drive product adoption and usage. Understanding of experimentation frameworks, statistical rigor, and the relationship between technical implementation and product experimentation velocity."}
- {"name":"Multi-region & Global Systems","description":"Experience architecting systems across geographic regions with considerations for data sovereignty, latency optimization, and eventually consistent data models. Understanding of payment rails and settlement across different markets."}
- {"name":"Provider Integrations","description":"Experience integrating with external payment providers, gateway APIs, and third-party financial services. Understanding of rate limiting, error handling, and maintaining resilience when depending on external services."}
- {"name":"Observability & Monitoring","description":"Expertise implementing comprehensive observability practices including structured logging, distributed tracing, metrics, and alerting. Experience diagnosing production issues in high-frequency transaction systems with minimal downtime."}
- {"name":"Open Source Contribution","description":"Active participation in open source projects, demonstrating commitment to community engineering standards and ability to write code for external consumption and peer review."}

## Tech stack

### tools

- {"name":"AWS Cloud Platform","description":"Primary cloud infrastructure provider hosting microservices, managing databases, implementing messaging systems, and providing observability tooling for payment systems running at billion-dollar daily volume."}
- {"name":"CI/CD Pipelines","description":"Continuous integration and deployment automation enabling rapid iteration while maintaining reliability and safety in payments systems handling billions in daily transactions."}
- {"name":"Infrastructure as Code","description":"Tools for defining and managing AWS resources programmatically, enabling reproducible deployments and disaster recovery across multiple regions."}
- {"name":"Observability & Monitoring Stack","description":"Comprehensive monitoring, logging, and tracing infrastructure for real-time visibility into payment processing, issue diagnosis, and performance optimization."}

### others

- {"name":"Payment Gateway Integrations","description":"Integration with external payment processors and providers, managing APIs, webhooks, error handling, and reconciliation across payment flows."}
- {"name":"AI-Powered Payment Automation","description":"Emerging technology for intelligent payment chasing, agentic payment workflows, and AI assistant integration, combining LLM capabilities with fintech domain logic."}
- {"name":"Experimentation Frameworks","description":"A/B testing and growth experimentation platforms enabling data-driven decision-making on payment features, checkout optimization, and user engagement."}
- {"name":"Financial Compliance & Regulatory Standards","description":"Understanding of payment industry regulations including PCI-DSS, data residency requirements, and anti-money laundering considerations across different geographic markets."}

### databases

- {"name":"SQL Databases","description":"Relational databases for transactional payment data, ledger records, and financial records requiring strong ACID guarantees and complex query capabilities."}
- {"name":"NoSQL Databases","description":"Non-relational stores for high-write-throughput scenarios, event logs, and user interaction data, providing eventual consistency and horizontal scalability."}
- {"name":"Ledger Systems","description":"Specialized data structures for tracking financial transactions, ensuring auditability, and maintaining double-entry accounting principles across payment flows."}

### languages

- {"name":"C#","description":"Primary backend language used across Xero's payments platform for building microservices and domain logic with strong typing and cloud-native support."}
- {"name":"Java","description":"Backend language utilized for high-throughput payment processing services, leveraging mature ecosystem and performance optimization capabilities."}
- {"name":"Go","description":"Used for building lightweight, concurrent services within the payments platform, particularly for API gateways and provider integrations with efficient resource utilization."}
- {"name":"C++","description":"Employed for performance-critical components requiring low-latency processing and minimal memory overhead in payment flow execution."}

### frameworks

- {"name":"Microservices Architecture","description":"Core architectural pattern organizing the payments platform across multiple independent services with clear boundaries, handling checkout, payment methods, provider integrations, and bill payments."}
- {"name":"Event-Driven Architecture","description":"Likely pattern for coordinating payment flows asynchronously, managing state transitions, and ensuring consistency across distributed payment components."}
- {"name":"API Gateway Pattern","description":"Central pattern providing the single product-agnostic API that other Xero teams consume, handling routing, authentication, rate limiting, and request transformation."}

## Benefits

### benefits

## Compensation

- **max:** 0
- **min:** 0
- **currency:** 
- **stockOptions:** false

## Interview process

### steps

## Full description
## **The role**

Xero reimagined accounting software. Now we’re reimagining how small businesses get paid and how money moves. We're making a critical, multi-year investment in two connected engineering portfolios, Payments Products & Experiences and Payments Platform, and we're hiring a Principal Engineer for each. As our three-year payments strategy reaches a turning point, you'll help shape what comes next, with domain-level influence over the next two to three years.

You'll shape technical strategy across multiple teams, partnering with senior stakeholders to turn complex requirements into scalable, resilient systems. Staying close to the technical detail, you'll set the example for a portfolio of 40 to 50 engineers. You'll also join a global community of Principal Engineers across Xero, driving engineering standards, architecture, and best practices.

You'll _Go Bold_ by setting long-term direction, and _Go Together_ by bringing product, engineering and senior stakeholders with you.

## **The teams**

**Payments Products & Experiences:** this portfolio is made up of our Get Paid and Growth teams, builds the checkout, payment methods, flexible payments and AI payment agents that help small businesses get paid on time. 

**Payments Platform:** this portfolio is the engine underneath, with provider integrations, bill payments and a single, product-agnostic API that other Xero teams build on. 

Together they move billions of dollars across more than 150,000 transactions a day, a number set to double as we grow into the UK and US.

## **The teams are currently working on**

* Tech stack: microservices across web, API and data layers, built in languages such as C#, Java, Go or C++, running on AWS with SQL and NoSQL data stores.
* Current focus: reviewing existing payments systems to work out what to extend, migrate or rebuild, alongside Growth experiments and AI-powered payment chasing.
* Future focus: a multi-year payments architecture covering agentic payment workflows, payments inside AI assistants and recurring payments.
* Global scale: replatforming payment methods and designing global rails and a ledger ready for new markets.

## **Where and how you can work**

You'll be based in Sydney or Melbourne, working a hybrid model that blends time together in our modern offices with the flexibility of working from home. Boost days bring teams together to connect and collaborate in person. With colleagues across Australia and the US and payment flows that run around the clock, you'll also work across time zones.

## **Some of the things we're looking for**

* You bring deep experience designing and running large-scale distributed systems in production, balancing reliability, performance and cost, and any payments or fintech experience is a real plus.
* API-first thinking is second nature, and you're at home across web, API and data layers, with fluency in at least one modern backend language, SQL and NoSQL stores, and cloud-native platforms, ideally AWS.
* Legacy-heavy systems are a puzzle you enjoy, and you make clear, practical calls on whether to extend, migrate or build while staying hands-on through pairing, spikes and code.
* A strong interest in utilising AI tooling is essential, as you will model how to use these technologies to automate tasks and improve engineering outcomes.
* Your background shows a deep curiosity for growth hacking and a proven ability to design and analyse A/B tests that drive product usage.
* You'll _Go Further_ by mentoring Staff and Senior engineers, shaping cross-team initiatives with Xero's Principal community and setting standards that lift engineering across Xero.

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.