Systems Engineer (£150k–£195k + Equity) at $25M Series A AI security startup

Company: Jack & Jill
Apply for the Systems Engineer (£150k–£195k + Equity) at $25M Series A AI security startup
Location: London
Job Description:

Job Title

Systems Engineer

Salary

£150k–£195k + Equity

Company Description

$25M Series A cybersecurity startup backed by Next47, Ten Eleven Ventures, and In-Q-Tel

Job Description

You will join an elite team building the foundational endpoint agent for a category-defining AI security platform. Using Rust, you will develop high-performance, low-level software that protects sensitive data in real-time across Windows, macOS, and Linux. This role is critical in enabling enterprises to adopt AI tools safely at scale.

Location

London, UK

Why this role is remarkable

  • Work at the bleeding edge of AI governance, building the security layer for a world where every enterprise employee uses an AI copilot.
  • Join a high-traction startup led by experienced founders who previously scaled Digital Shadows, supported by top-tier investors like In-Q-Tel and Next47.
  • Total ownership over core architecture with a highly technical team that values Rust, memory safety, and high-performance systems engineering.

What You Will Do

  • Design and optimize security agent components in Rust, ensuring sub-500ms inference and zero-touch data protection on user devices.
  • Conduct technical research to implement cross-platform signals and controls for data movement across Windows, macOS, and Linux subsystems.
  • Build robust, CI-tested deployment mechanisms for client-facing releases that maintain high reliability and performance under real-world conditions.

The ideal candidate

  • Deep production experience in Rust or C++ with a strong focus on systems programming concepts like memory safety, concurrency, and IPC.
  • Proven track record building security-critical client software such as endpoint agents, EDR/XDR components, or low-level OS utilities.
  • AI-forward mindset with the ability to leverage modern tools like Claude Code or Cursor to accelerate high-expertise systems development.

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Posted: May 31st, 2026