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Principal Security Engineer

Reactor· Engineering
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San FranciscoFull TimePosted 2w ago

About the role

Reactor is hiring a Principal Security Engineer to build and lead Reactor's security program, protecting models and data for partners and customers, and integrating security into shipping processes.

Responsibilities

  • Set Reactor's security strategy and own it end-to-end
  • Protect the models and data our partners and customers trust us with
  • Threat-model the platform and fix what you find
  • Lead partner and customer security reviews and compliance work
  • Represent Reactor's security work with partners, customers, and the wider security and AI community
  • Build security into how the team ships
  • Set up detection and incident response across the organization

Qualifications

  • You've led security, or been one of the senior people on a security team, at an AI lab, a GPU cloud, or a cloud infra company
  • You write code, and like to be hands-on
  • Deep experience securing cloud-native infrastructure
  • You've taken a company through a compliance framework like SOC 2 and handled enterprise security reviews while keeping engineering moving
  • People in security or AI know your work: talks, published research, open source, or a track record at a company whose name carries weight
  • You are able to communicate complicated technical security problems across both technical and non-technical audiences
  • You want to work at an early-stage startup: small team, lots of ownership, fast pace, in person in SF

Skills

Required:Security leadership and program buildingCloud-native securityCompliance and enterprise security reviewsCommunication

Benefits

  • Salary and equity at the 99th percentile for our stage (Pave benchmarks)
  • Visa sponsorship and relocation support
  • Generous health, dental, and vision coverage
Last updated Oct 15, 2026. Interested? Apply on the company site.

About Reactor

Company profileWebsite

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