Senior Ledger Systems Engineer – AI-Enabled Banking

FIS Management Services; Greater London; On-site; GBP 90,000 - 140,000; Full time

Job summary

FIS is building Ledger Store, a replicated double-entry ledger, to record every money movement on the platform. You will own the design, deployment and production operation of this critical component, ensuring exact-once processing, low latency and high throughput across cloud and on-prem environments.

We value autonomy, technical depth, and ownership from design through production. You will work in a senior engineering team focused on correctness, performance, and scalable architectures, with

Qualifications

• Experience building and operating a distributed or durable system in production.
• Able to reason about concurrency, consistency and idempotency.
• Strong performance awareness and bottleneck identification.
• Production ownership with on-call or incident response exposure.
• Language-agnostic; Rust welcome, ability to learn needed tools.

Responsibilities

• Own system through design, implementation, testing and production operation.
• Balance correctness, latency, throughput and operational complexity.
• Establish observability and alerting to detect failures.
• Participate in on-call and incident response.
• Produce clear design notes and operational docs.

Skills

Distributed systems

Concurrency/Consistency

Performance optimization

Production ownership

AI-assisted engineering

Tools

Rust

MCP servers

Agent workflows

Job description

FIS is building Ledger Store, a replicated double-entry ledger, to record every money movement on the platform. You will own the design, deployment and production operation of this critical component, ensuring exact-once processing, low latency and high throughput across cloud and on-prem environments.

We value autonomy, technical depth, and ownership from design through production. You will work in a senior engineering team focused on correctness, performance, and scalable architectures, with