Senior Distributed Ledger Engineer

Fidelity Information Services, LLC; Greater London; On-site; GBP 120,000 - 180,000; Full time

Job summary

Fidelity Information Services, LLC (FIS) is building Ledger Store, a replicated double-entry ledger powering AI-enabled banking platforms for Tier-1 institutions. You will design, implement, operate and scale a low-latency, high-throughput system across cloud environments and on-prem deployments.

We value ownership and accountability, with engineers taking initiative from design through production. Strong judgement on correctness and performance, plus collaboration, are essential to success in

Qualifications

• Experience building distributed or durable systems in production.
• Ability to reason about concurrency, consistency, idempotency and failure modes.
• Understanding of memory management, allocation, and concurrency effects on runtime.
• Language-agnostic approach; willingness to learn required tools.
• Experience debugging critical systems and participating in on-call or incident response.
• Ability to evaluate alternatives and explain trade-offs.
• Clear communication of complex systems in reviews and notes.
• Thoughtful use of AI to improve engineering quality and safety.

Responsibilities

• Own systems through design, implementation, testing, deployment and production operation.
• Make trade-offs between correctness, latency, throughput and operational complexity explicit.
• Establish observability and alerting to help engineers detect failures and understand causes.
• Take part in on-call and incident response; address root causes and prevent related failures.
• Deliver small, traceable changes supported by tests and measured results.
• Use AI-assisted development, MCP servers and agent workflows where they improve outcomes.
• Mentor colleagues and write clear design notes, reviews and operational documentation.

Skills

Systems experience

Correctness

Performance

Programming depth

Production ownership

Engineering judgement

Communication

AI-assisted engineering

Job description

Fidelity Information Services, LLC (FIS) is building Ledger Store, a replicated double-entry ledger powering AI-enabled banking platforms for Tier-1 institutions. You will design, implement, operate and scale a low-latency, high-throughput system across cloud environments and on-prem deployments.

We value ownership and accountability, with engineers taking initiative from design through production. Strong judgement on correctness and performance, plus collaboration, are essential to success in