Principal Security Engineer

Reactor; San Francisco (CA); On-site; USD 180,000 - 250,000; Full time

Benefits offered by this job

Salary and equity package

Visa sponsorship

Health insurance

Job summary

Reactor is hiring a Principal Security Engineer in San Francisco to build and own Reactor's security program from the ground up. You will protect models and data, lead security reviews, and drive compliance with partners and customers in a fast-paced startup environment.

You will be hands-on, set the security strategy, and represent the security function with external stakeholders. This role requires deep cloud security expertise and the ability to communicate complex concepts to both technical

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

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

Skills

Security leadership

Hands-on security engineering

Cloud security

SOC 2 compliance

Communication

AI/ML security

SF in-person

Job description

Description

Reactor is building the inference platform for real-time world models. Our goal is to democratize access to real-time intelligence to unlock next-generation use cases in media, physical AI and omni-directional models. We already run the largest and fastest catalog of world models on the market, and work closely with all major model labs to run and optimize their world models, including Alibaba, Amazon, and NVIDIA. Our team is made of alumni from leading firms such as Apple, Meta, Amazon, Microsoft, Luma AI, Adobe, Stability AI, and more. We've raised $74M led by Lightspeed, with Amplify Partners, WNDR, NVIDIA, Sapphire, and other Tier 1 investors participating. Jeffrey Katzenberg, co-founder of DreamWorks Animation, sits on our board of directors.

Department

Engineering

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