Principal Engineer (Auth)

Methodfi; United Kingdom; Remote; GBP 106,000 - 189,000; Full time

Job summary

A cybersecurity firm in the United Kingdom is seeking a Principal Engineer to lead the authentication service. This role focuses on performance optimization, security, and collaborative leadership within a small team that values autonomy. Candidates should have over 8 years of experience in building production systems, with a strong preference for proficiency in Rust or Go. This position offers a competitive salary and the opportunity to contribute to critical security solutions.

Qualifications

• 8+ years of experience building and operating production systems.
• Experience in Rust or Go strongly preferred.

Responsibilities

• Own the authentication service for security products.
• Work with team to optimize system performance and security.
• Collaborate across teams to understand customer needs.

Skills

Systems Programming in Rust or Go

Performance Optimization

Secure Systems Engineering

Asynchronous Programming

Problem-Solving for Legacy Rewrites

Commitment to Testing

Collaborative Leadership

Strategic Use of AI Tools

Job description

Overview

Menlo Security's mission is enabling the world to connect, communicate and collaborate securely without compromise. We support customers across various enterprises including Fortune 500 companies, 9/10 of the largest global banks and the Department of Defense. We are growing and seeking passionate talent with empathy and agility to join our team as a principal engineer to own our authentication service.

The authentication service is at the root of our browser security product. Every user request flows through it, so the decisions you make here have real consequences for security, performance, and system evolution. You will work with a small team that values autonomy and ships with minimal process overhead, bringing technical leadership to an existing system and team.

What We\'re Looking For

• Strong Systems Programming Background: Extensive hands-on experience building and maintaining production systems in Rust or Go, with a preference for languages that offer strong safety guarantees in critical applications.
• Passion for the Craft: You care about building software the right way. Correctness, scalability, and maintainability matter beyond just delivering a feature.
• Focus on Performance Optimization: Demonstrated ability to optimize for latency and throughput in networked applications, using profiling tools and efficient concurrency models.
• Security-Oriented Engineering Practices: Strong background in implementing secure systems, with a proactive approach to threat modeling, vulnerability mitigation, and data integrity in distributed environments.
• Expertise in Asynchronous Programming: Built and operated async services that handle high concurrency in production. You understand back-pressure, cancellation, and non-blocking I/O failure modes.
• Problem-Solving for Legacy Rewrites: Experience refactoring legacy codebases into more robust architectures, evaluating trade-offs in language choices while favoring long-term maintainability and security.
• Commitment to Testing and Verification: History of comprehensive testing strategies, including fuzzing, property-based testing, and integration tests to validate correctness under various failure scenarios.
• Collaborative Technical Leadership: Ability to articulate and defend architectural decisions in team settings, mentoring others on secure software development.
• Strategic Use of AI Tools: Proficiency in leveraging AI thoughtfully to boost productivity while ensuring architectural correctness and maintainability.
• Ownership: Responsible for the full lifecycle of the services you build, working with team members who have deep context of the system.
• Communication: Work with your team and across teams to understand customer needs, refine requirements, implement, review, and deliver changes.

Requirements

• 8+ years of experience building and operating production systems
• Experience in Rust or Go strongly preferred

Our Compensation and Benefits

Base salary range for this role is $145,000 - $255,000, with competitive total compensation and benefits. The actual amount may vary based on experience, knowledge, skills, abilities, and location, in compliance with applicable law.

Employees may be eligible for stock-based compensation grants based on company and individual performance.

Equal Opportunity and Compliance

Menlo Security is an equal opportunity employer. All aspects of employment are based on merit, competence, performance and business needs. We do not discriminate on the basis of race, color, religion, marital status, age, national origin, ancestry, physical or mental disability, medical condition, pregnancy, genetic information, gender, sexual orientation, gender identity or expression, veteran status, or any other status protected by law.

MSGL-I4

All qualified applicants will receive consideration for employment without regard to race, sex, color, religion, sexual orientation, gender identity, national origin, protected veteran status, or disability.

TO ALL AGENCIES: Please, no phone calls or emails to any employee outside of the Talent organization. Only resumes from agencies via approved processes will be considered; any resume submitted outside of this process may be deemed the property of Menlo Security.

Reasonable accommodations provided upon request in accordance with applicable law.