Founding Sr Full-Stack Engineer
Founding Sr Full-Stack Engineer at Helium — San Francisco, CA, US
- Company: Helium
- Location: San Francisco, CA, US
- Employment type: FULL_TIME
- Salary: USD 150000–250000 / year
- Posted: 2026-07-17
About this role
Helium is building Self-Improving Software: AI that automatically generates & tests new software experiences to lift revenue. We’re…
Talent-dense (8 people, 6 engineers, 75% ex-founders)
Well-funded ($6M from Google & Leaders from OpenAI)
Fast-growing (Serving tens of millions of AI experiences per day for top consumer companies).
AI has created a once-in-history opportunity, and we’re here to win, because of that…
🔴 We work hard — In-Office Monday–Friday + often push through weekends 🔴
What You’ll Do
You’ll own big chunks of our AI Experience Generation product serving millions of users per day, including…
Adding new features to the front-end Next.js application and deploying scalable Golang code that serves thousands of requests each second globally.
Tune/Optimize/Load test our servers as we 10x our growth from tens of millions to hundreds of millions of users per day.
Designing data systems and ML training infrastructure that power automated experimentation at scale.
Work directly with founders and customers to design, implement, and deliver the best experiences!
Wearing a lot more hats than listed above 👷.
What We’re Looking For
Keen problem solving skills: you are able to cut down ambiguous problems down to first principles and deliver a working solution.
Strong programming/full-stack foundation: You’re comfortable working on both backend code as well as frontend React code.
Experience working directly on user-facing products: you are able to figure out and understand what the user needs, including talking to customers
Stellar cross-functional communication skills: you are able to adapt to our ways of working and be an efficient/effective communicator.
Owning features end to end: you’ll write your own PRDs/quick specs when necessary, and you test your features end to end to make sure they work and satisfy the requirements
Experience scoping, designing, and running complex multi-engineer projects
Experience managing or mentoring engineers before
Nice To Haves
Experience with ML/AI/LLM integration in applications
Experience building scalable backend systems with very demanding SLAs
Background working with design tools, chat experiences, or vibe coding tools
Previous experience founding or working at a high-growth startup
Reasons This Role Might Not Be A Fit
You want to work 9-5
You avoid Cursor or AI coding tools.
You can only operate on well-written specs, or feel uncomfortable designing new experiences from scratch.
You don’t want to talk to customers.
Our stack:
Next.js (React/Typescript), Zustand
AI (vercel) SDK
Tailwind/Shadcn
Supabase
Clickhouse
Golang/Fly.io
Mobile: Swift, Flutter, Expo, Android
Requires Bachelors degree or higher in Computer Science or similar fields.