Full-Stack Engineer

Company: Confidential - Venture-backed AI infrastructure startup
Location: San Francisco, CA (in person, 5 days per week)
Compensation: $200,000 (about 3 years of experience) up to $300,000 (3-7 years); exceptional candidates case by case
Employment Type: Full-time
Visa Sponsorship: Case by case for exceptional candidates

About the Company

A venture-backed startup building monitoring infrastructure for production AI agents, surfacing behavioral issues such as instruction drift that traditional observability misses. Hundreds of agent-building teams rely on its platform.

The Role

Our client is hiring a Full-Stack Engineer to own the product experiences and agent infrastructure that make the agent improvement loop clear and actionable for engineering teams. You will talk to customers, decide what to build, build it and iterate until it is great, across the data layer, the UI, agent-swarm interfaces, verification platforms and the SDK. About 30% of the role is customer-facing.

What You Will Do

• Shape how the the company Agent runs large parallel investigations across thousands of production traces and merges findings into one actionable answer.
• Build the platform for verifying agent changes: hosted simulated environments, trajectory replay and monitors for unintended behavior.
• Make long agent traces, tool calls and failures understandable in minutes.
• Build the swarm UX for watching and redirecting parallel investigations.
• Own the improvement loop that turns production trajectories into datasets, judges and regression checks.
• Build the SDK and terminal-first experience, and platform infrastructure such as workspaces, roles, permissions, billing and limits.

What You Bring

• 3-7 years of experience building and scaling end-to-end production systems, from data layer to UI
• Hands-on experience building with LLMs or agents, or the drive to get there fast
• Comfort working directly with customers (about 30% of the role)
• Strong problem-solving in fast-changing, ambiguous environments
• Clear, direct, persuasive communication
• Based in San Francisco or willing to relocate; in person 5 days a week

Nice to Have

• Evals, observability or agent behavior-monitoring products
• Engineering pedigree from a strong product or infrastructure company
• Forward-deployed or solutions engineering experience
• Early-hire 0-to-1 startup experience or a founder background

Benefits

Full benefits package, Equinox membership, a private chef, and direct influence on the product roadmap.