Founding Full-Stack Engineer
Helium, San Francisco, California
- Pay
- $125K–$200K / year
- Work type
- Not stated
- Level
- Not stated
- Area
- Software engineering
- Posted
- Jan 8, 2026
About the 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
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
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Listed on Y Combinator's job board; checked 29 h ago. First seen by us 29 h ago. Being listed doesn't mean the team is actively interviewing.