AI / Systems Engineer, Security Research APPLIED AI SYSTEMS KERNEL LOW-LEVEL New York, NY / On Site →

Zealot Labs, Inc.; Greater London; Hybrid; GBP 105,000 - 165,000; Full time

Benefits offered by this job

Skin in the game equity

Job summary

Zealot Labs, Inc. is seeking a strong low-level systems engineer to join a small, ownership-driven team in London. You will work on AI-driven vulnerability research, operating system internals, and performance-critical code that ships to production.

The role demands a deep fluency close to the metal and a willingness to operate in a fast-paced startup environment. The position requires in-person presence in London five days a week, with full relocation support and eligibility for U.S.

Qualifications

• 2+ years of engineering experience. Open to exceptional new grads with demonstrated low-level systems work.

Responsibilities

• Build production systems that conduct AI-driven vulnerability research and exploit development at scale.
• Work close to the metal: operating system internals, kernel-level interfaces, and low-level performance optimization.
• Own problems end-to-end across architecture, implementation, and shipped production code.
• Partner directly with vulnerability researchers, security operators, and the engineering team to convert manual cyber operations into automated, repeatable systems.
• Help define the standards and operating cadence of a team that intends to set the bar for AI-native cyber.

Skills

Low-level systems

Kernel development

OS internals

Performance optimization

C/C++ experience

Production code

London in-person

Job description

Zealot is deploying AI systems at the center of western cyber operations , backed by tier-1 US VCs and industry leaders. Our team includes alumni of Anthropic, xAI, and Anduril. Soon live with close U.S. allies abroad.

APPLIED AI SYSTEMS KERNEL LOW-LEVEL

Compensation 105K-165K + skin in the game equity

Location London, United Kingdom On Site

Stage Early-stage startup backed by tier 1 investors. Small, growing team with exceptionally high ownership.

• + Build production systems that conduct AI-driven vulnerability research and exploit development at scale.
• + Work close to the metal: operating system internals, kernel-level interfaces, and low-level performance optimization.
• + Own problems end-to-end across architecture, implementation, and shipped production code.
• + Partner directly with vulnerability researchers, security operators, and the engineering team to convert manual cyber operations into automated, repeatable systems.
• + Help define the standards and operating cadence of a team that intends to set the bar for AI-native cyber.
• + 2+ years of engineering experience. Open to exceptional new grads with demonstrated low-level systems work.
• + Deep low-level systems experience: operating system internals, kernel work, runtime detection, dynamic analysis, dynamic interception, or comparable. This is non-negotiable.
• + Strong builder mindset. Comfortable owning systems end-to-end and shipping production code where performance and correctness matter.
• + Comfort with ambiguity and uncertainty. The most important cultural requirement.
• + Willing to be in person in London 5 days per week. Full relocation support provided.
• + Eligible for the security clearances and customer requirements associated with U.S. government work.

Nice to Have

• + Vulnerability research, CTF, or prior security research experience.
• + Prior YC company as founder or early engineer.
• + Engineering experience at xAI, Anthropic, Scale, Palantir, or similar high-bar AI companies.
• + Open-source contributions to OS-level tooling.
• + Cyber or security startup engineering experience, especially runtime detection, dynamic analysis, or operating system tooling.
• + Exposure to ML/AI systems work.
• + A low-level systems builder first. The non-negotiable is fluency close to the metal; speed is the team's defining operating value.
• + Comfortable owning problems end-to-end, optimizing for real hardware, and shipping production systems where performance and correctness matter.
• + Building something massive matters more to you than comfort, titles, or predictability.
• + You want to be early at a company that will change an industry, and you're ready to do what that actually takes.

Ready?