Backend Engineer - Payments Platform (Scale & Reliability)

SmartRecruiters, Inc.; Greater London; On-site; GBP 68,000 - 88,000; Full time

Job summary

Wise is hiring in London for a backend engineer to design, develop and maintain high-volume payment services. You will build RESTful APIs, work with PostgreSQL databases and Kafka, and ensure secure, scalable processing of billions in payments.

You will contribute to an on-call rotation, participate in code reviews, and collaborate with cross-functional teams to deliver reliable, cost-efficient payment orchestration across providers.

Qualifications

• Backend engineer with experience designing and maintaining high-volume payment systems.
• Proficient in Java or Kotlin and Spring Boot.
• Experience with cloud deployment (AWS) and RESTful APIs.

Responsibilities

• Design, develop, test, and maintain backend services written in Java and Kotlin using the Spring Boot framework, deployed on cloud infrastructure (AWS)
• Build and maintain RESTful APIs that serve millions of customers across web and mobile platforms
• Develop and optimise services powering the card payin payment method — one of the most popular payment methods, enabling Wise customers to move around £1 billion every month
• Design and implement database schemas, write and optimise SQL queries against PostgreSQL databases handling high-volume transactional data
• Build and maintain event-driven architectures using Apache Kafka for asynchronous processing of financial events across distributed services
• Develop and maintain a payment orchestration system that dynamically routes payments across Payment Service Providers to optimize for cost and reliability
• Write automated tests (unit, integration, and end-to-end) to ensure correctness and reliability of financial systems
• Conduct code reviews for team members, ensuring code quality, security, and adherence to engineering standards
• Participate in on-call rotations to monitor and respond to production incidents for Tier 2 critical services
• Collaborate with product managers, designers, analysts, and engineers across other teams to deliver cross-functional projects
• Identify and resolve performance bottlenecks, scalability issues, and technical debt in existing systems
• Ensure development follows security best practices, particularly around handling of sensitive financial data and compliance with financial regulations

Skills

Java

Kotlin

Spring Boot

AWS

REST APIs

PostgreSQL

Kafka

SQL

Testing

Code reviews

On-call

Tools

Kafka

PostgreSQL

AWS

REST

Job description

Wise is hiring in London for a backend engineer to design, develop and maintain high-volume payment services. You will build RESTful APIs, work with PostgreSQL databases and Kafka, and ensure secure, scalable processing of billions in payments.

You will contribute to an on-call rotation, participate in code reviews, and collaborate with cross-functional teams to deliver reliable, cost-efficient payment orchestration across providers.