Principal Software Engineer

 

Description:

Principal Software Engineer, Platform, BPL

As an Engineering Lead in our Chief Product and Technology Office (CPTO), you’ll shape the architecture of tomorrow and mentor talented engineers, crafting elegant solutions for complex problems to create solutions that millions depend on.

In this role you'll be at the forefront of innovation, designing and building highly resilient, scalable distributed services that power critical business operations.

You'll work with modern JVM languages (primarily Kotlin), cloud-native technologies, and contemporary frontend frameworks.

What You’ll Be Building

World-Class Distributed Systems - Design and implement highly performant, fault-tolerant distributed services that handle massive scale with grace. You'll architect systems that are built to survive failures, scale elastically, and deliver lightning-fast response times.

Domain-Driven Excellence - Apply domain modelling principles to create clean, maintainable codebases that accurately represent complex business logic. Your work will set the standard for engineering excellence.

Production-Grade Quality - Champion comprehensive testing strategies—from unit tests to performance testing to chaos engineering. You'll ensure every service is battle-tested before it sees production traffic.

Full-Stack Impact - Build responsive web UIs that delight users while maintaining the performance and reliability standards expected of enterprise-grade applications.

Ownership -Live the "you build it, you run it" philosophy. You'll participate in on-call rotations (shared across the team), giving you direct insight into how your systems perform in the wild and driving continuous improvement.

Security First - Embed security into every layer of your solutions, ensuring customer data is protected with industry-leading practices and zero-trust principles.

AI-Augmented Development -Leverage AI-powered tools to accelerate development while ensuring every line of code—whether human or AI-generated—meets our exacting production standards.

Successful candidates will have a storied history with extensive experience building complex, scalable systems. You’ve seen things break at scale, and you know how to prevent it.

Essential Skills Include

 

  • Experience gained in a Payment Acquiring, Fintech or Payment SaaS business.
  • Product thinking approach - you treat the platform as a product, with fellow engineers as your customers
  • Sophisticated communication - demonstrating the ability to bring both technical and non-technical stakeholders on the journey with us, e.g. explaining complex technical trade-offs to those who might not know what a "service mesh" is
  • A polyglot mindset with expertise of at least two languages and "right tool for the job" philosophy
  • JVM Mastery – Deep expertise in at least one JVM language (we primarily use Kotlin, but strong Java, Scala, or Clojure experience translates beautifully)
  • Cloud-Native Mindset – Hands-on experience with cloud platforms (AWS, Azure, GCP) and understanding of cloud design patterns
  • Messaging & Events – Solid grasp of messaging technologies (Kafka, RabbitMQ, SQS, NATS) and event-driven architecture patterns
  • Data Layer Expertise – Experience with both SQL (PostgreSQL, MySQL) and NoSQL (MongoDB, DynamoDB, Redis) databases, understanding when to use each
  • API Design – Proven track record designing and implementing RESTful and/or GraphQL APIs that scale
  • Rust – Experience with systems programming and performance-critical services
  • AWS Mastery – Advanced AWS knowledge
  • Kubernetes – Container orchestration experience with K8s, Helm, and cloud-native deployment strategies
  • React – Modern frontend development skills with React, TypeScript, and state management libraries
  • Observability – Experience with monitoring, logging, and tracing tools
  • CI/CD Wizardry – Strong DevOps mindset with experience in automated deployment pipelines, infrastructure as code, and GitOps practices

Organization Barclays
Industry IT / Telecom / Software Jobs
Occupational Category Principal Software Engineer
Job Location London,UK
Shift Type Morning
Job Type Full Time
Gender No Preference
Career Level Intermediate
Experience 2 Years
Posted at 2026-06-02 1:49 pm
Expires on 2026-07-17