HartleyCo
Founding AI Engineer (San Francisco Bay Area)
HartleyCo, San Francisco, California, United States, 94110
Founding AI Engineer (YC-backed Voice + Text AI Startup)
Location:
San Francisco, CA (in person) Perks:
Team housing available in San Francisco
The Company Our client is a YC-backed seed-stage startup building the
simulation, evaluation, and observability layer for voice and text AI agents . Their platform is already being used by enterprises and high-growth startups, including Fortune 500 companies, to ensure conversational AI agents perform safely, reliably, and at scale.
With $4M raised from leading investors (including Floodgate and PeakXV) and revenue doubling every quarter since launch, theyre now hiring a
Founding AI Engineer
to join their core team in San Francisco. This is a chance to work alongside the founders, directly influence the product roadmap, and help define the technical foundation of a rapidly growing AI company.
The Role This is a full-stack role with a strong AI focus. The ideal candidate is hands-on, deeply technical, and comfortable building across the stack. Youll be designing systems that simulate, test, and measure AI agents in real time - powering the infrastructure that ensures AI products behave as intended.
Responsibilities
Architect and develop systems that
simulate, analyze, and evaluate conversational AI agents
across voice and text. Design scalable, resilient infrastructure on AWS (Lambda, EC2, WebSockets, SIP) to handle thousands of simultaneous real-time interactions. Build and optimize pipelines that
measure agent performance, detect failure modes, and enforce reliability and safety . Ship production-grade code across frontend and backend systems with full ownership from design to deployment. Collaborate directly with enterprise customers to build, test, and deploy solutions in real-world environments.
Tech Stack
Frontend:
React, TypeScript, Next.js, Tailwind Backend:
Python, FastAPI, Redis, Supabase Infrastructure:
AWS (Lambda, EC2, WebSockets, CI/CD) Voice AI:
LiveKit, Deepgram, Cartesia, ElevenLabs Text AI:
Pydantic AI, OpenAI, agentic frameworks
Ideal Profile
Full-stack engineer with strong fundamentals and a track record of shipping real products. Excited by
Voice AI, LLMs, and real-time AI systems . Passionate about clean architecture, code quality, and efficient design. Entrepreneurial mindset; thrives in fast-moving, high-ownership environments. Strong communicator and collaborator who enjoys working closely with technical founders.
Nice to Have
Experience in
Voice AI , conversational agents, or LLM evaluation pipelines. Prior work at a
YC-backed startup
or as a
Founding Engineer . Background in
RAG systems, reinforcement learning, or multi-agent frameworks . Strong product sensibility and eye for user experience or system aesthetics.
Logistics
In-person only
role in San Francisco. US work authorization required
(open to OPT if no onboarding delay). Interview process: informal culture fit call
practical system design exercise
optional technical validation
short
paid work trial .
Why Its Worth Your Time This company is defining a new category for AI quality assurance - engineering trust into how AI agents are tested before deployment. Youll be working with high-profile customers, advanced AI systems, and founders who have already proven their ability to ship, sell, and scale.
If you want to build at the intersection of
AI safety, infrastructure, and real-world impact , this is an opportunity to join a YC startup early, take real ownership, and grow with the company.
To express interest or learn more, reach out directly to
Josh Kelly at HartleyCo , the retained search partner for this hire.
San Francisco, CA (in person) Perks:
Team housing available in San Francisco
The Company Our client is a YC-backed seed-stage startup building the
simulation, evaluation, and observability layer for voice and text AI agents . Their platform is already being used by enterprises and high-growth startups, including Fortune 500 companies, to ensure conversational AI agents perform safely, reliably, and at scale.
With $4M raised from leading investors (including Floodgate and PeakXV) and revenue doubling every quarter since launch, theyre now hiring a
Founding AI Engineer
to join their core team in San Francisco. This is a chance to work alongside the founders, directly influence the product roadmap, and help define the technical foundation of a rapidly growing AI company.
The Role This is a full-stack role with a strong AI focus. The ideal candidate is hands-on, deeply technical, and comfortable building across the stack. Youll be designing systems that simulate, test, and measure AI agents in real time - powering the infrastructure that ensures AI products behave as intended.
Responsibilities
Architect and develop systems that
simulate, analyze, and evaluate conversational AI agents
across voice and text. Design scalable, resilient infrastructure on AWS (Lambda, EC2, WebSockets, SIP) to handle thousands of simultaneous real-time interactions. Build and optimize pipelines that
measure agent performance, detect failure modes, and enforce reliability and safety . Ship production-grade code across frontend and backend systems with full ownership from design to deployment. Collaborate directly with enterprise customers to build, test, and deploy solutions in real-world environments.
Tech Stack
Frontend:
React, TypeScript, Next.js, Tailwind Backend:
Python, FastAPI, Redis, Supabase Infrastructure:
AWS (Lambda, EC2, WebSockets, CI/CD) Voice AI:
LiveKit, Deepgram, Cartesia, ElevenLabs Text AI:
Pydantic AI, OpenAI, agentic frameworks
Ideal Profile
Full-stack engineer with strong fundamentals and a track record of shipping real products. Excited by
Voice AI, LLMs, and real-time AI systems . Passionate about clean architecture, code quality, and efficient design. Entrepreneurial mindset; thrives in fast-moving, high-ownership environments. Strong communicator and collaborator who enjoys working closely with technical founders.
Nice to Have
Experience in
Voice AI , conversational agents, or LLM evaluation pipelines. Prior work at a
YC-backed startup
or as a
Founding Engineer . Background in
RAG systems, reinforcement learning, or multi-agent frameworks . Strong product sensibility and eye for user experience or system aesthetics.
Logistics
In-person only
role in San Francisco. US work authorization required
(open to OPT if no onboarding delay). Interview process: informal culture fit call
practical system design exercise
optional technical validation
short
paid work trial .
Why Its Worth Your Time This company is defining a new category for AI quality assurance - engineering trust into how AI agents are tested before deployment. Youll be working with high-profile customers, advanced AI systems, and founders who have already proven their ability to ship, sell, and scale.
If you want to build at the intersection of
AI safety, infrastructure, and real-world impact , this is an opportunity to join a YC startup early, take real ownership, and grow with the company.
To express interest or learn more, reach out directly to
Josh Kelly at HartleyCo , the retained search partner for this hire.