Senior Principal Software Engineer - Core Banking Platform

FIS; Greater London; Hybrid; GBP 120,000 - 180,000; Full time

Job summary

FIS in London, within a newly acquired startup building an AI-enabled, autonomous banking platform for Tier-1 institutions, seeks a senior engineer to own core banking services from design to production. You will design APIs, ensure correctness, scale distributed systems, and lead incident response with observability and reliable deployments.

This role offers startup autonomy within a global enterprise. Strong Go or equivalent language experience, event-driven architectures, and a practical bias

Qualifications

• Deep experience designing and building complex distributed systems at scale.
• Strong understanding of concurrency, invariants, and failure modes.
• Experience with event-driven architectures and modern production practices.

Responsibilities

• Build and evolve banking capabilities from products to transactions and compliance.
• Define APIs, events, and data contracts for a coherent platform.
• Own services through design, testing, deployment, and operation.
• Contribute to observability, incident response, and reliability improvements.
• Promote engineering best practices and knowledge sharing.

Skills

Distributed systems

Go

Event-driven architecture

Kafka

Concurrency & consistency

Incident response

Observability

CI/CD

Tools

Kafka

GitOps

CI/CD tooling

Job description

FIS in London, within a newly acquired startup building an AI-enabled, autonomous banking platform for Tier-1 institutions, seeks a senior engineer to own core banking services from design to production. You will design APIs, ensure correctness, scale distributed systems, and lead incident response with observability and reliable deployments.

This role offers startup autonomy within a global enterprise. Strong Go or equivalent language experience, event-driven architectures, and a practical bias