Principal Software Engineer - Payments

Masabi; Greater London; Hybrid; GBP 120,000 - 150,000; Full time

Job summary

Masabi is seeking a Principal Engineer - Payments to lead architecture across the payments domain, shaping technical direction and guiding scalable, cost-efficient solutions used by millions of journeys worldwide.

You will work with cross-functional teams to design distributed systems, partner with PSPs, and drive adoption of modern microservices while balancing delivery and platform health. This is a senior, hands-on role with strategic impact.

Qualifications

• Strong payments experience with PSPs, gateways, EMV, contactless EMV and acquirers.
• Understanding of payment flows, transaction lifecycles and system design.
• Experience designing distributed systems and microservices architectures.
• Operated at Principal or Staff level, shaping technical direction across teams.
• Strong judgement balancing delivery with long-term architecture outcomes.
• Ability to navigate ambiguity and turn complex problems into practical approaches.
• Clear communicator across technical and non-technical audiences.
• Hands-on when needed while focusing on system-level impact.
• Experience with cloud platforms (AWS preferred) and modern infra practices.
• Familiarity with scalable, reliable, and cost-aware decision making.
• Exposure to AI-enabled systems and production implications.

Responsibilities

• Shape the technical direction of Masabi’s payments platform, architecture, standards and engineering best practices.
• Design and deliver scalable, secure, resilient payment solutions aligned with platform direction.
• Support teams toward a modern microservices-based architecture while balancing delivery priorities and platform health.
• Stay close to technical delivery through architecture reviews and hands-on contribution.
• Identify and solve complex scalability, resilience, and performance challenges.
• Advise across engineering teams on payments domain decisions.
• Collaborate with external providers on integrations and problem-solving.
• Contribute to technical roadmap planning, scoping and architecture discussions.
• Produce clear technical documentation and promote engineering standards.

Skills

Payments systems

Distributed systems

Microservices

AWS experience

Tools

Terraform

GitLab CI/CD

DynamoDB

MySQL

Kotlin

Java

Job description

// At Masabi, we’re driving the fare payment revolution, powering the journeys of millions all over the world. We build fare collection platforms that allow riders to seamlessly buy and present tickets for public transport either on their mobile phones, from a ticket machine, or even by tapping their bank card to travel.

The Role_

// We’re looking for a Principal Engineer - Payments to join Masabi’s Architecture team, with a primary focus on our payments domain.

This is a senior role for someone who combines strong technical judgement with deep payments experience. You’ll help shape the technical direction of our payments platform while staying close enough to the detail to design, review and support meaningful technical work.

Working across the engineering organisation, you’ll act as a senior technical leader within the payments domain - contributing to architecture, guiding complex decisions and helping teams build scalable, resilient systems that support millions of journeys worldwide.

The role suits someone who can move between system-level thinking and implementation, who understands trade-offs, can navigate ambiguity and helps turn complex or loosely defined problems into clear, practical technical approaches.

Location_

// This role is open to candidates based anywhere in the UK, with the flexibility to work fully remotely. For those based in or around London, we also offer the option of hybrid working from our London office.

Responsibilities_

• Shape the technical direction of Masabi’s payments platform, contributing to architecture, standards and engineering best practices
• Design and deliver scalable, secure, resilient and cost-effective payment solutions aligned with Masabi’s platform direction
• Support teams in building towards a modern, microservices-based architecture while balancing delivery priorities and long-term platform health
• Stay close to technical delivery through architecture reviews, design discussions and targeted hands‑on contribution where needed
• Identify and work through complex technical challenges related to scalability, resilience, operational performance and system evolution
• Act as a senior technical advisor across engineering teams, supporting and influencing technical decisions, particularly within the payments domain
• Work with external providers and payment partners on integrations, technical alignment and problem‑solving
• Contribute to technical roadmap planning, prioritisation, technical scoping and architecture discussions for complex initiatives
• Produce clear technical documentation and contribute to engineering standards, technical forums and good practices across the organisation

About You_

// You bring a mix of strong technical expertise, sound judgement and real-world payments experience.

• Strong experience working on payment systems, including integrations with PSPs, gateways, EMV, contactless EMV, acquirers, etc.
• Good understanding of payment flows, transaction lifecycles and system design considerations
• Experience designing and evolving distributed systems and microservices architectures
• You’ve operated at Principal or Staff level, shaping technical direction across multiple teams or domains
• Strong judgement and the ability to balance short-term delivery with long-term architectural outcomes
• Comfortable navigating ambiguity and turning complex problems into clear, practical technical approaches
• Clear and thoughtful communicator, able to engage both technical and non-technical audiences
• Comfortable being hands‑on where needed, while maintaining a focus on system‑level impact
• You have strong experience with cloud platforms (AWS preferred) and modern infrastructure practices
• You’ve worked on systems where scale, reliability, performance and cost trade-offs matter, and can navigate those decisions thoughtfully
• You’ve contributed to engineering standards, architecture patterns or platform direction
• Interest in or exposure to AI‑enabled systems, particularly understanding architectural implications in production

Nice To Have_

• Experience with transit systems or fare payment systems (e.g. tap-to-ride systems)
• Familiarity with card schemes (e.g. Visa, Mastercard, Interac)
• Experience working in complex, multi‑service or event‑driven architectures
• Familiarity with a range of tools and technologies including:
• Development: Kotlin, Java
• Data storage: DynamoDB, MySQL
• Infrastructure as code and CI/CD: Terraform, GitLab CI/CD

// You don’t need to have experience in every area listed above. If you bring strong fundamentals, good judgement, and a willingness to learn, we’d still love to hear from you.

Why Join Masabi?

• Driven by Purpose – We believe in journeys made simple. The work isn’t always easy, but the best things never are.
• Encouraged to Accelerate – Masabi is going places and our people are in the driving seat. Whether you’re taking the direct route or exploring new paths, we support your journey.
• Advancing with Empathy – We put people first and foster a culture of learning, not blame. No matter your cargo, we share the load.