Senior Founding Engineer

SENIOR FOUNDING ENGINEER

Overview

We now handle millions of calls per month and need an engineer who has worked at that scale before and knows how to build systems that dont break under it. This is an architecture-heavy full-stack role not just backend. You will own everything from database optimization to reducing dashboard load times from four seconds to sub-100 milliseconds.

Were looking for someone in their late 20s who has moved fast inside engineering teams that move fast brings solid practices into a growing codebase and is the kind of person who has put hundreds of hours into mastering something outside of work. If youve never taken a hobby to an extreme this is not the role for you.

You will work on-site at the SF office (moving to a larger space in three months) directly with the founding team.

About the Company

The company is the worlds first quality assurance agency for voice and text AI building the simulation evaluation and observability layer for conversational AI agents. Founded by former AI engineers at Microsoft and AWS the company makes sure AI agents perform as intended before they ever reach the real world.

Backed by Y Combinator Floodgate and PeakXV the company grew to over $100K in ARR in under a month during YC and has been doubling growth every three months since inception. They have crossed the $1M revenue mark and are now handling millions of calls per month. Clients include Google DoorDash Sallie Mae and 11X with more Fortune 500 names being added every quarter.

Key Responsibilities

Architect and develop systems that simulate analyze and evaluate conversational AI agents across voice and multimodal formats

Design resilient scalable infrastructure using AWS (Lambda EC2 WebSockets SIP) to handle millions of real-time conversations

Reduce system bottlenecks across the stack from database query optimization to frontend dashboard performance

Develop algorithms and pipelines that surface insights detect failure modes and ensure agents are safe reliable and aligned with human intent

Establish and enforce strong engineering practices across code review architecture design and system design

Work on-site with customers to build sell and deploy the product in real environments

Requirements Must Have

6 years of full-stack engineering experience with demonstrated depth across frontend and backend

Deep proficiency in TypeScript Python SQL and AWS (non-negotiable)

Strong systems and architecture thinking can design at scale and articulate why

Experience building and optimizing production systems at a significant scale (millions of requests large data volumes)

Low ego high communication ability; if youre hard to talk to its not a fit

Has taken something outside of work to an extreme (competitive gaming rank sub-12-second Rubiks Cube solve athletic record anything that required hundreds of hours of deliberate practice to achieve)

US citizenship or permanent residency strongly preferred

H-1B transfer considered

Tech Stack

Frontend: React Tailwind TypeScript NextJS

Backend: Python FastAPI Supabase Redis AWS (Lambda EC2 WebSockets SIP)

Voice AI: LiveKit Deepgram Cartesia ElevenLabs Gemini

Other: WebSockets CI/CD

Requirements Nice to Have

Prior experience as a founding engineer at a YC company (6 months)

Background in voice AI or conversational AI systems

Has built polished high-quality frontend web products

Technical ex-founder with VC-backed startup experience

Background at high-bar AI companies

Compensation

Base Salary: $200000 - $250000

Benefits & Perks

Health insurance

Gym membership comped if you go 5 times per month

$500 desk and workspace setup stipend

Interview Process

1. Intro call with Founder

2. Take-home assignment

3. Technical interview

4. On-site work trial

5. Offer Extended