Founding Engineer – Full-Stack

CGS; San Francisco (CA); On-site; USD 180,000 - 240,000; Full time

Benefits offered by this job

Founding equity

Unlimited AI spend

Daily lunch

Job summary

CGS in San Francisco is seeking a Founding Full-Stack Engineer to own and shape the platform across infrastructure, agent systems, and user-facing features. You’ll work directly with the founders to deliver practical AI-powered solutions that manage complex business workflows.

The role emphasizes end-to-end ownership, reliability, and collaboration with customers and the founding team. This is an in-person, full-time opportunity with significant early-stage impact.

Qualifications

• Strong full-stack engineering capabilities with a solid infrastructure and systems background.
• Experience shipping software across both product and platform layers.
• Proven ability to build reliable production software, ideally AI agents or workflows that users depend on.
• Strong understanding of architecture, system design and engineering trade-offs.
• Ability to take ownership of projects from initial design through production deployment.
• Attention to detail and a strong sense of product quality, particularly UI and UX.
• Comfortable working directly with customers through calls, onboarding or support.
• Willingness to work full-time in person in San Francisco, five days a week.
• Early-career candidates are welcome, but must demonstrate exceptional engineering ability.

Responsibilities

• Build and improve core agent infrastructure and orchestration systems.
• Develop memory, recommendation systems and long-running agent execution capabilities.
• Build internal applications and user-facing product features.
• Work across backend, frontend, infrastructure and platform engineering.
• Improve the reliability and performance of AI agents used for real business workflows.
• Develop and maintain evaluations that measure actual agent performance.
• Build scalable systems that support complex, multi-step business tasks.
• Work closely with the founders and customers to understand requirements and deliver practical solutions.

Skills

Full-stack engineering

System design

Ownership

UI/UX quality

Customer interaction

Job description

Working model: Full-time, in-office (5 days a week)

Working hours: 9 AM – 5 PM, Monday to Friday

Experience: 1+ years (exceptional early-career candidates considered)

About the company

A profitable, seed-stage AI company in San Francisco is building a platform that acts as an internal workforce for businesses. Its AI agents can take ownership of complete business tasks, such as managing accounts receivable through Slack or scheduling through email. Businesses can also use the platform to build their own internal applications.

With a two-person founding team and customers acquired primarily through referrals, the company is now looking for two founding engineers to help shape its next stage of growth.

The role

As a Founding Full-Stack Engineer, you'll work across the entire technology stack, from core infrastructure and agent systems to user-facing product experiences. You'll help build the platform that enables AI agents to execute complex, long-running tasks reliably, while also developing the applications and interfaces that businesses use every day.

The immediate focus is making agents more capable and reliable, supported by hundreds of thousands of interaction traces every week.

This is a broad engineering role with significant ownership. You'll work directly with the founders, influence technical direction and help build the foundations of the company.

What you'll do

• Build and improve core agent infrastructure and orchestration systems.
• Develop memory, recommendation systems and long-running agent execution capabilities.
• Build internal applications and user-facing product features.
• Work across backend, frontend, infrastructure and platform engineering.
• Improve the reliability and performance of AI agents used for real business workflows.
• Develop and maintain evaluations that measure actual agent performance.
• Build scalable systems that support complex, multi-step business tasks.
• Work closely with the founders and customers to understand requirements and deliver practical solutions.

What we're looking for

• Strong full-stack engineering capabilities, with a solid infrastructure and systems background.
• Experience shipping software across both product and platform layers.
• Proven ability to build reliable production software, ideally AI agents or workflows that users depend on.
• Strong understanding of architecture, system design and engineering trade-offs.
• Ability to take ownership of projects from initial design through production deployment.
• Attention to detail and a strong sense of product quality, particularly UI and UX.
• Comfortable working directly with customers through calls, onboarding or support.
• Willingness to work full-time in person in San Francisco, five days a week.

Early-career candidates are welcome, but must demonstrate exceptional engineering ability through standout internships, founder experience, competitive achievements or other strong evidence.

What makes you stand out

• Experience building production AI agents or workflows that users rely on.
• Experience with agent memory, long-running execution and evaluation systems.
• Background at a strong engineering organisation such as Decagon, Harvey, Factory or Ramp.
• Previous founder experience or participation in a founder fellowship.
• Competitive achievements in programming, mathematics, debate or games.
• Experience as a forward-deployed or solutions engineer who builds production code.
• A strong engineering portfolio demonstrating polished, detail-oriented product work.
• Become one of the first engineering hires alongside a two-person founding team.
• Take ownership across infrastructure, platform and product development.
• Help shape the architecture and direction of a growing AI company.
• Work on real-world AI agents already handling complete business workflows.
• No hour tracking or close day-to-day management: ownership and output matter.
• Unlimited AI spend and daily lunch provided.
• Meaningful founding equity and the opportunity to make a significant impact.
• Founder screen (30 minutes): Background, previous projects, communication, authenticity of experience and willingness to adopt new tools.
• Technical interview (60 minutes): Deep dive into one project from your CV, covering architecture, design decisions, personal ownership, reliable agents, memory, long-running execution and evaluations.
• Practical assessment: Either a 2–4 day work trial or a 1–2 day take-home assignment.
• Reference checks and offer.