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

People Hive HR Consultancies LLC is acting as the recruitment partner for this vacancy. Applications will be handled confidentially and shared with the client as part of the recruitment process.

Job Reference: PH-ANS-109