Job Description

Founding Full-Stack Engineer

San Francisco | US Citizens Only | Onsite

Our client is building the end-to-end testing platform for voice + text AI. Backed by Y Combinator, Floodgate, and top angels, they are already working with Fortune 500s and the hottest voice AI startups in Silicon Valley. With $4M in funding and a small but world-class team, they are growing fast and looking for thier first Founding Engineer to help shape the future of conversational AI.

What You'll Do

As a founding engineer, youll be a full-stack builder and problem-solver:

• Architect and scale systems that simulate, analyze, and evaluate conversational AI agents (voice + multimodal).
• Design resilient AWS infrastructure (Lambda, EC2, Websockets, SIP) to handle thousands of real-time conversations.
• Develop algorithms and pipelines that surface insights, detect failure modes, and keep AI safe, reliable, and aligned with human intent.
• Work directly with customers to deploy, test, and refine the product in real-world settings.
• Own features end-to-end from conception to deployment ensuring clean, maintainable code and scalable systems.

Tech Stack

Python, React, TypeScript, Next.js, FastAPI, Tailwind, PostgreSQL, Redis, Supabase, AWS, Websockets, CI/CD
Voice AI tools: LiveKit, Deepgram, Cartesia, ElevenLabs, Gemini, Pydantic AI, OpenAI

What Were Looking For

• 1+ years of experience as a full-stack or founding engineer at an early-stage recognised Invested startup
• Strong experience with Python, React, PostgreSQL, and AWS .
• Bonus: exposure to voice AI technologies (LiveKit, Deepgram, ElevenLabs, Cartesia, Gemini).
• Previous role at a high-bar engineering company (e.g., Meta, Google, Microsoft) or a fast-growth startup (YC, top VCs).
• CS degree or equivalent practical experience.
• Excited to work onsite in San Francisco with a small, close-knit team.
• Creative hobbies (e.g., YouTube, design, art) are a plus we love builders with imagination.

Why Join

You'll learn more in a month than years at Big Tech. As a founding engineer, you'll:

• Have real decision-making power over architecture, product, and direction.
• Work directly with Fortune 500 clients and fast-growing startups.
• Build with cutting-edge AI tools and ship fast.
• Join an incredibly close-knit team at our HQ, The Nest .

About our client

Founded by ex-Microsoft and AWS engineers, they graduated from YC X25 and grew to $100K ARR in just two weeks. Trusted by some of the worlds largest enterprises they are quickly becoming the gold standard for testing conversational AI.

Apply now to get in with this exciting career opportunity, or DM to find out more

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