hirly

Security Level 5

Network Engineer

San Francisco, CA

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hirly's read of this role

Seniority
Mid level
Stated salary
$200,000 – $350,000 per year
Country
US
Work mode
On-site / unstated
First seen by hirly
28 Sept 2026

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the posting

About Security Level 5

Security Level 5 is a Bay Area AI security nonprofit working with AI labs and US intelligence agencies to defend frontier models from priority nation-state-level threats. We move fast, and we're tripling headcount this year.

The Mission

We're hiring for what's plausibly the most difficult, urgent, and interesting challenge in AI security engineering this decade (for humans, at least): designing and building the first datacenter purpose-built to Security Level 5, the standard for defending frontier AI labs against attackers with the resources of a nation-state and billion-dollar budgets. We're working on the first SL5 components this year and aiming for an at-scale SL5 datacenter build in 2027.

We wrote the first version of the standard with input from CISOs and senior security staff at the frontier labs, and US security and intelligence officials. Now we're designing the SL5 architectures purpose-built for frontier AI workloads, and standing up the reference tech stack to guide labs' buildouts. This stack has to hold against nation-states, not destroy researchers' productivity, not cost more than labs can pay, and ship in 2-3 years.

What you'd work on

Designing and operating the network fabric of the environment: switch configuration, segmentation and the controlled links between the SL5 network, Weight Enclave and other segments in the air-gapped network. This may involve working on an egress bandwidth limiter, building the gateways / tunnels for remote media stations and remote users and more.

Owning the identity and trust layer: the signing / PKI service (or its baked-key alternative), domain services and audit logging.

You'd be a fit if you

Have experience turning a trust boundary on paper into an enforced one in practice, e.g. configuring segmentation / egress controls and verifying via counters, logs or testing.

Have run identity, PKI / code signing or similar services in an on-prem or disconnected environment.

Can employ a security mindset to ensure properties of a design are translated to reality.

Logistics

Bay Area, in-person. This role's base salary range is $200,000 - $350,000 USD per year. We may be open to paying exceptional and/or highly experienced employees more than this. We also provide full benefits, including healthcare, dental, vision, 401k match, and more.

Original posting on Security Level 5's site ↗

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