Senior/Staff Founding Full-Stack Engineer - Agent Systems

People Hive is supporting an early-stage AI infrastructure client in San Francisco in the search for a highly skilled Senior/Staff Founding Full-Stack Engineer – Agent Systems.

The successful candidate will join the company's early-stage team and help build complex systems from the ground up, with significant influence over the future of the product and technical architecture.

The client is developing AI coworkers specifically for IT teams , with a strong focus on security, identity, authorization and reliable agent execution.

While the position is heavily focused on backend engineering and systems, the successful candidate will own the product end-to-end, working across infrastructure, APIs and user-facing experiences.

The role includes developing workflow systems capable of supporting long-running human and AI agent tasks, designing identity and authorization systems, and building secure credential infrastructure. The engineer will also work on sandboxed environments and production-grade APIs supporting next-generation AI systems.

Critical Requirements

• 4+ years of professional software engineering experience
• Proven experience designing and operating complex production systems
• Strong backend and systems architecture proficiency
• Ability to work in person in San Francisco, Monday through Friday
• High level of ownership and ability to navigate ambiguity

Important Requirements

• Experience working across frontend, infrastructure, data and product layers
• Background in security, IAM, authorization or workflow orchestration
• Experience with multi-tenant SaaS or AI infrastructure
• Strong understanding of failure modes, threat models and system reliability
• Ability to move quickly without compromising security or correctness

Nice to Have

• Experience with permission and identity systems
• Experience with secrets or privileged-access platforms
• Experience with workflow engines and reconciliation systems
• Experience with agent infrastructure and evaluation systems
• Experience with sandboxes or virtualized execution
• Experience with enterprise integrations
• Previous experience in an early-stage startup with ownership of architecture and production

About the Client

The client is a fast-growing pre-seed AI infrastructure startup building foundational technology for AI agents, with a particular focus on security and reliability.

The company provides a collaborative, high-impact environment for engineers who want to build complex systems from the ground up and have significant ownership over architecture and production.

Benefits

• Competitive compensation
• Health insurance
• Unlimited PTO
• Office meals
• Visa sponsorship available for qualified candidates, including H-1B, O-1 and OPT

Location: San Francisco, California, USA

Working arrangement: On-site, Monday to Friday

Employment: Full-time

Seniority: Senior

Industry: AI Infrastructure

Salary: $200,000–$300,000 per year