Founding Backend Engineer — AI Agent Infra, Equity 0.5–1%

CGS; San Francisco (CA); On-site; USD 180,000 - 280,000; Full time

Job summary

CGS, a seed-stage AI company based in San Francisco, is hiring its third engineer to own the core backend infrastructure and scale coding-agent sessions. You will design agent sandboxes, AI gateways, and orchestration in a hands-on role that shapes the architecture and product direction.

Expect to work on production systems from scratch with high autonomy, collaborating closely with founders. Five days on-site, 9-9-6 schedule, eligibility limited to US citizens or Green Card holders.

Qualifications

• 3+ years hands-on software engineering experience; 5+ years preferred.
• Recent experience as an IC at a fast-growing seed-stage or Series A startup.
• Proven experience designing and building production backend systems from scratch.
• Strong understanding of distributed systems, infrastructure and performance optimisation.
• Experience with TypeScript or Python, PostgreSQL, AWS and containers.
• Able to explain and defend architectural decisions, including why one approach was chosen.
• Genuine interest in AI coding agents and developer tooling.
• Comfortable working fully on-site in San Francisco, five days per week, on a 9-9-6 schedule.
• Must be a US citizen or Green Card holder. No sponsorship available.

Responsibilities

• Design and build core backend systems and infrastructure from the ground up.
• Own agent sandboxes, AI gateways and orchestration for large-scale coding-agent sessions.
• Solve real-world challenges involving system performance, reliability and scalability.
• Make independent technical decisions and take responsibility for the architecture.
• Ship customer-facing improvements quickly, incorporating feedback within days rather than weeks.
• Work closely with the founders and contribute to technical direction and product decisions.

Skills

Backend engineering

Distributed systems

TypeScript

Python

PostgreSQL

AWS

Containers

Tools

ClickHouse

Docker

Kubernetes

Job description

CGS, a seed-stage AI company based in San Francisco, is hiring its third engineer to own the core backend infrastructure and scale coding-agent sessions. You will design agent sandboxes, AI gateways, and orchestration in a hands-on role that shapes the architecture and product direction.

Expect to work on production systems from scratch with high autonomy, collaborating closely with founders. Five days on-site, 9-9-6 schedule, eligibility limited to US citizens or Green Card holders.