Senior / Principal Rust Engineer

Juxt Ltd.; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Hybrid work model

Full medical

10% matched pension

Premium events

Job summary

Juxt Ltd. is seeking experienced Rust engineers for a demanding systems and performance programme with a global financial leader. You will rewrite core parts of an equities execution platform in Rust, focusing on ultra-low latency and careful memory layout to minimize tail latency.

The team is small, AI-assisted, and adheres to automated testing as non-negotiable. Work is hybrid with UK-based candidates who can attend the London area office at least three times a week.

Qualifications

• Experience writing allocation-free, latency-conscious Rust for hot paths.
• Strong understanding of latency distributions and tail latency minimization.
• Knowledge of CPU caches, memory layout, and NUMA awareness and their impact on latency.
• Proven automated testing discipline including deterministic replay and simulation.
• Experience with AI-assisted engineering tools is a plus.

Responsibilities

• Rewrite core parts of an equities execution platform in Rust.
• Build fast, reliable near-metal systems with automated tests.
• Collaborate with a small, AI-assisted team to define production Rust standards.

Skills

Rust programming

Low-latency systems

Performance measurement

Automated testing

AI-assisted tooling

Tools

Tokio

Claude Code

Job description

Job Description

We're looking for experienced Rust engineers to join us on a demanding systems and performance programme with a global financial leader.

You'll join a small, exceptional team rewriting core parts of an equities execution platform in Rust, where ultra-low latency is the whole point. These are systems that sit close to the metal and leave no room for error, and this is work for people who enjoy understanding how things behave all the way down, from the type system to the memory layout to the way the kernel schedules their code. The teams are deliberately small, heavily AI-assisted, and hold automated testing as non-negotiable.

Rust is central to this role. You'll use its ownership model and zero-cost abstractions to build software that is both fast and hard to get wrong, and you'll help set the standards for how we write, test and operate Rust in production. There's also scope to shape how we bring AI tooling to bear on systems-level work.

If you enjoy solving hard problems, measuring rather than guessing, and building things you can be proud of, you'll feel right at home.

Core skills

• Deep, hot-path Rust is essential: writing allocation-free, contention-aware code on the critical path, with careful control of memory layout and data structures
• A firm understanding of latency distributions and how to minimise tail latency (p99.9 and beyond) is essential, along with proven experience building ultra-low-latency, low-jitter systems
• Mechanical sympathy: a real feel for how CPU caches, memory layout and contention shape latency, and the techniques used to control them (CPU affinity, NUMA awareness and the like)
• Familiarity with the techniques used to squeeze latency out of the network and OS path, such as kernel bypass and busy-polling I/O
• Rigorous measurement: latency histograms, tail-latency analysis and an awareness of coordinated omission
• Strong automated testing discipline, treated as essential: property-based tests, deterministic replay and simulation
• AI-assisted engineering e.g. Claude Code, etc.
• Clear communication skills and the ability to articulate design and performance decisions

Nice to have

• Equities execution or market-structure knowledge (cash equities, prime, OMS, smart order routing or FIX). Strongly preferred
• Experience with matching engines, market data, or exchange or HFT-grade systems
• Async Rust and Tokio for control-plane and tooling work, distinct from the hot path
• Experience contributing to open-source or internal frameworks

What we offer

• Work on a high-profile, long-term programme with a global financial leader. You'll have a significant impact, and a chance to build systems that you can be proud of.
• Work in a talented team, learning from exceptional colleagues with a real focus on getting things done.
• Opportunities for learning and growth, including exposure to the latest AI technologies and practices.
• Great benefits, including full medical, 10% matched pension and regular premium events.

WFH?

These roles are hybrid, a mix of remote work and on-site collaboration. You'll need to be UK-based and within a commutable distance of London and able to attend the office at least 3 times per week if required.

Contract type

Permanent and contract roles available.

Eligibility

Applicants should have a permanent right to work in the UK.