Endpoint Engineer (Senior Rust/C++ Developer)

Harmonic, Inc.; City of Westminster; Hybrid; GBP 60,000 - 80,000; Full time

Job summary

A pioneering cybersecurity firm in the UK is seeking an endpoint engineer to develop security-critical client software. The role involves using Rust to optimize endpoint security components, conduct technical research, and collaborate closely with engineers and stakeholders. Ideal candidates should possess hands-on Rust experience, a strong foundation in systems programming, and a passion for ensuring high-quality, performant software. The company offers competitive pay, comprehensive benefits, and a supportive team environment.

Benefits

Competitive pay

Pension plan

Generous PTO

Annual global offsites

Qualifications

• Strong hands-on experience with Rust (or C++ with willingness to learn Rust) in production systems.
• Solid grasp of systems programming concepts: memory safety, lifetimes, threads, channels.
• Familiarity with platform APIs on Linux, Windows, and macOS.

Responsibilities

• Design and implement endpoint security components in Rust.
• Build validation tooling and deployment mechanisms for client releases.
• Conduct research for new product feature implementation.

Skills

Rust programming

C++ development

Systems programming

Memory safety

Networking skills

Tools

Git

CI pipelines

Job description

Overview

As AI adoption accelerates inside the enterprise, Harmonic's ability to safely observe, control, and enforce policy at the endpoint is mission-critical. This role sits at the core of that challenge. As an endpoint engineer, you'll help build and evolve the low-level, security-critical client software that powers Harmonic's platform. Our software must be fast, resilient, and trustworthy across operating systems and real-world conditions. You\'ll have the opportunity to shape foundational agent architecture, influence how we collect and process signals on-device, and set the technical bar for correctness and safety as we define a new category of AI security. About the Team Our Product Delivery team is the engine that turns vision into impact. We ship early and often, getting valuable features into the hands of customers quickly and iterating from there. We work in the open by default, sharing progress and ideas, and we trust each other to own outcomes. We\'re a small but mighty crew where every person plays a critical role and we\'re committed to using AI to work smarter and faster, We\'re looking for a hands-on systems engineer with deep expertise in Rust (or C++ with a strong willingness to learn and embrace Rust as your primary language) to help us build and evolve security critical client software. You will work on low level security agents and cross platform components that run on user devices, with a strong emphasis on robustness, performance and security. Your work will power core functionality in how we collect signals, and manage on-device controls for app usage and data movement. You will join a fast-moving team that ships frequently and cares about correctness, observability and maintainability.

What You\'ll Do

• Design, implement, and optimise endpoint security agent components in Rust, targeting desktop and/or server platforms (Windows, macOS, Linux)
• Build robust tests, validation tooling and deployment mechanisms for client facing releases that impact our customers in their everyday work
• Conduct exploratory technical research to understand the art of the possible and how to best approach implementation of new product features
• Investigate and resolve platform specific issues with precision and speed
• Work closely with security engineers, backend engineers, and product stakeholders to shape technical requirements
• Flourish in the Unknown: We relish being thrown into new, unfamiliar situations that require initiative and rapid decision-making. We orient ourselves quickly and deliver results with minimal guidance.
• Never Full: We never hesitate to raise our hands and take on challenges to assist those in need. We hunger for opportunities to learn and do more.
• Perfect Harmony: We have a genuine willingness to assist and support one another to create cohesion and unity. We foster success through collaboration and honest sharing of feedback and ideas, enabling everyone to grow and produce their best work.
• You\'ve shipped production Rust or C++ code that runs safely and efficiently across platforms
• Your components are well tested, observable, and resilient to partial failures or bad input
• You identify performance or architectural bottlenecks before they reach users
• You actively reduce complexity in critical code paths without compromising clarity or functionality
• You consistently deliver high-quality changes on a tight feedback loop, including regression-safe updates

Requirements

• Strong hands-on experience with Rust (or C++ with a strong willingness to learn Rust) in production systems
• Solid grasp of systems programming concepts: memory safety, lifetimes, threads, channels, error handling, IPC
• Familiarity with platform APIs and subsystems on Linux, Windows and macOS
• Experience building CI-tested, reproducible builds for native applications
• Proficiency with common developer tooling: Git, code review, CI pipelines, structured logging, crash analytics
• Networking skills and security fundamentals is a plus

You Might Be a Fit if You…

• Have a strong development background and a rigorous approach to testing and validation
• Relish the prospect of writing code that will run on millions of devices and needs to be reliable and performant around the clock
• Enjoy working close to the OS and care deeply about software performance, correctness and safety. Previous Kernel or system-level development experience is a great nice-to-have
• Can build and ship reliable systems fast, with a sharp eye for edge cases and long term impact and maintainability
• Learn quickly and independently, with great attention to detail and high standards
• Have made contributions to open-source Rust (or C++) projects or RFCs
• Believe that good tooling and documentation are part of engineering, not afterthoughts
• Thrive in fast-paced startup environments where ambiguity is the norm
• See AI as a tool to help you build smarter, faster and better

Why Join Us

• This isn\'t just a job; it\'s an opportunity to be part of a team that is redefining cybersecurity. We believe today\'s talent is tomorrow\'s success, and we\'re committed to creating an environment where you can do the best work of your life.
• Competitive pay and meaningful equity with a direct stake in Harmonic\'s success
• Comprehensive benefits, pension plan, generous PTO, and flexible hybrid work
• A small, passionate team that values transparency, creativity, and learning
• Thoughtful leadership that cares deeply about growth, impact, and people
• Annual global offsites (past trips include Lisbon and Nashville)
• The chance to directly shape both our product and our culture as we build a category-defining company