Senior Product Engineer - Founding Team, AI Security - $260k + Equity

limitless; San Francisco (CA); On-site; USD 234,000 - 286,000; Full time

Benefits offered by this job

Founding equity

Brand new SF office

Job summary

Limitless is seeking a Senior Product Engineer to join as part of the founding team in San Francisco. You will build the core platform from the ground up, partnering with the founders to define product direction and architecture, with a focus on AI agent capabilities.

This role centers on a TypeScript stack (Node and React). You’ll play a key part in shaping engineering culture and delivering secure, scalable systems as the team grows.

Qualifications

• Strong product engineering experience in TypeScript (Node and React).
• Experience building AI agents or agentic systems is highly desirable.
• Solid backend and distributed systems fundamentals.

Responsibilities

• Build and own core backend and data infrastructure the platform runs on.
• Help design the architecture behind the company’s AI agents.
• Ship product end to end across TypeScript (Node and React).
• Work directly with the founders to shape product direction and technical decisions.
• Help shape engineering standards as the team grows.
• Build production-grade systems with emphasis on reliability and security.

Skills

TypeScript

Node.js

React

AI agents

Distributed systems

Tools

AI/ML backends

Job description

Senior Product Engineer - Founding Team, AI Security - $260k + Equity

Limitless is partnering exclusively with a VC backed AI security startup tackling one of the biggest open problems in security right now: keeping companies safe as AI changes how software gets built and shipped.

The founders are repeat operators with a successful exit behind them and deep experience leading security at some of the world’s largest technology companies. They’ve since advised and invested across the tech ecosystem, and now they’re building again with a harder problem and a stronger team.

The company recently raised one of the larger seed rounds in the security space this year, giving them serious runway to build. The team is still small and intentionally lean.

About the Role

They’re looking for a Senior Product Engineer to join as one of the first 10 people and help build the core platform from the ground up.

This is a product engineering role across a TypeScript stack (Node and React). You’ll work directly with the founders to define product and platform, and experience building AI agents is a real advantage.

It’s ideal for someone who wants a genuine founding seat with a team that has already built and scaled a successful security company, and who wants to be in the room every day while it happens.

Key Responsibilities

• Build and own core backend and data infrastructure the platform runs on
• Help design the architecture behind the company’s AI agents
• Ship product end to end across TypeScript (Node and React)
• Work directly with the founders to shape product direction and technical decisions
• Help shape engineering standards and practices as the team grows
• Build production-grade systems where reliability and security are non-negotiable

What Success Looks Like

• A backend foundation the whole platform can scale on
• AI agents shipping reliably to customers
• Fast, high-quality product iteration alongside the founders
• A strong engineering culture and codebase that future hires want to join

What We’re Looking For

• Strong product engineering experience in TypeScript (Node and React)
• Experience building AI agents or agentic systems, whether that’s orchestration, production AI backends or eval infrastructure
• Solid backend and distributed systems fundamentals
• Experience with graph or complex data infrastructure is a big plus
• A background in security, cloud infrastructure or developer tooling, the closer the better
• Based in the Bay Area (or ready to relocate) and up for being onsite 5 days a week
• A builder at heart, motivated by a hard problem and a great team

Interview Process

• 2 screening calls
• 1 onsite (2-3 sessions)
• Offer

Why Join?

• Proven founders: a previous exit (top ten in Europe) and leadership pedigree from big tech security
• Well funded: a substantial seed round $22m and long runway
• Founding-stage impact: one of the first 10 hires, building the core of the platform
• Hard problem: securing how software gets built in the AI era
• Package: $260k base plus meaningful founding equity, in a brand new SF office

Senior Product Engineer - Founding Team, AI Security - $260k + Equity