Principal Software Engineer

This London-based Principal Software Engineer role sits at the heart of Verifone's global payment gateway platform. You will help shape the technical direction of systems responsible for processing high-volume, mission-critical financial transactions worldwide.

At this level, the role goes beyond feature delivery. You will drive architectural decisions, set engineering standards, and influence how teams design, build, and operate secure, scalable backend systems. Success in this role is defined by technical leadership, sound judgment in complex trade-offs, and ownership of systems that must perform reliably under real-world load and regulatory constraints., We are seeking a Principal Software Engineer based in London to provide technical leadership across backend services supporting our global payment gateway system. You will design and evolve core platform capabilities, guide architectural decisions across microservices, and mentor engineers while remaining hands-on with critical systems built using Java and Spring Boot.

You will work closely with senior engineering, platform, product, and infrastructure partners to ensure our systems scale globally, remain secure, and meet the highest standards for availability and performance.

Do you have experience in System design?, * Spring Boot

• Spring Web (REST APIs)
• Spring Data
• Spring Security with JWT / OAuth2

Architecture & System Design

• Deep experience designing and operating microservice-based architectures
• Strong application of clean code practices and SOLID principles
• Ownership of system-level architecture and cross-service design decisions
• Strong understanding of security, authentication flows, and data protection in distributed systems

API & Data

• Design and governance of RESTful APIs, JSON, and HTTP standards
• API versioning and backward-compatibility strategies
• MongoDB / NoSQL expertise, including:

• Data modeling
• Indexing strategies
• Performance optimization

• Advanced experience with Java concurrency, streams, and performance tuning

Cloud & Infrastructure

• AWS services including EC2, ECS/EKS, S3, RDS and/or DynamoDB, and CloudWatch
• Docker and containerized deployments
• CI/CD pipelines and Git-based workflows
• Experience designing systems for scalability, resilience, and operability

Testing & Engineering Practices

• Strong unit and integration testing practices using JUnit and Mockito
• Ownership of quality standards, testability, and CI discipline
• Experience working in Agile / Scrum environments and influencing engineering best practices, * Principal-level backend engineering experience building and operating large-scale, high-performance systems
• Approximately 8+ years of backend development experience, with several years working on production Java and Spring Boot services
• Proven experience owning architecture and technical direction for critical backend platforms
• Extensive production experience with MongoDB, including modeling, indexing, and performance optimization

Preferred Skills and Experience

Payments & Domain Expertise

• Background in fintech or payments
• Experience with payment processing, transactions, and financial data
• Strong understanding of high-availability, security, and data-consistency trade-offs

Eventing & Distributed Systems

• Experience with event-driven architectures
• Messaging or streaming technologies such as:

• Kafka
• AWS SQS
• Similar eventing systems

Platform & Technical Leadership

• Deep experience with AWS, Docker, and CI/CD practices
• Proven ability to mentor engineers and raise the technical bar across teams
• Strong sense of ownership for systems running in production

For more than 30 years, Verifone has been a global leader in electronic payment technology. We work with leading retailers, merchants, banks, and technology partners to deliver secure, reliable, and innovative payment solutions worldwide. Verifone offers a fast-paced, collaborative environment focused on engineering excellence, customer impact, and continuous innovation. We are proudly an in-office organization and currently support a hybrid work model, which is reviewed regularly. We offer a fast-paced, collaborative environment focused on results, innovation, and customer impact. Verifone is proudly an in-office culture, with a hybrid work schedule currently available and reviewed regularly.