Principal Security Engineer

Reactor

• $160K — $200K *
Information Technology
Less than 5 years of experience
Job Overview by Ladders

Qualifications

  • 5-7 years of experience in security roles at AI labs, GPU clouds, or cloud infrastructure companies
  • Hands-on coding skills
  • Extensive knowledge of securing cloud-native infrastructure
  • Experience with compliance frameworks like SOC 2
  • Recognized in the security or AI community through talks, research, or notable company experience
  • Ability to communicate complex security issues to diverse audiences
  • Desire to work in a fast-paced, early-stage startup environment

Responsibilities

  • Set and own Reactor's security strategy end-to-end
  • Protect models and data for partners and customers
  • Conduct threat modeling and address vulnerabilities
  • Lead security reviews and compliance efforts with partners and customers
  • Represent Reactor's security initiatives to external stakeholders
  • Integrate security practices into the development process
  • Establish detection and incident response protocols across the organization

Benefits

  • Salary and equity at the 99th percentile for the company's stage
  • Visa sponsorship and relocation support
  • Comprehensive health, dental, and vision coverage
Full Job Description
Principal Security Engineer

Department: Engineering

Employment Type: Full Time

Location: San Francisco

The Role

We're hiring a Principal Security Engineer. You'll build Reactor's security program from the ground up, and you'll be the person partners and customers talk to about how we protect their models and data.

What You'll Do
  • 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


What We're Looking For
  • 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

Nice to Have
  • Experience securing model weights or ML infrastructure
  • Real-time or media infrastructure, anywhere p99 matters more than the average
  • GPU cluster security
  • Red team or offensive security experience


What We're Not Looking For
  • Policy or GRC leaders who haven't touched infrastructure in years
  • People who need a team of 10 before anything gets done
  • Compliance checklists with no threat model behind them

Logistics
We're in person in San Francisco

Benefits
  • Salary and equity at the 99th percentile for our stage (Pave benchmarks).
  • Visa sponsorship and relocation support
  • Generous health, dental, and vision coverage

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