SECTION I · THE BRIEF
Brief #74968Updated 22 AUG 2026SAN FRANCISCO, CAYc
Employbl Company Profile

Founding Sr Full-Stack Engineer

Helium is hiring a Founding Sr Full-Stack Engineer in San Francisco, CA. Full brief — comp band, interview process, and hiring team — available to Employbl members.

Location
San Francisco, CA
Company size
1–10
Posted
3d ago
Via
Yc
Section II · Premium ProfileMembers only
  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Hiring manager & team contextLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked
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Founding Sr Full-Stack Engineer · Helium

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Job title
Founding Sr Full-Stack Engineer
Job location
San Francisco, CA, US
Job listing URL
https://www.ycombinator.com/companies/helium/jobs/n4tOZ3R-founding-sr-full-stack-engineer
Job description
**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](http://Fly.io) * Mobile: Swift, Flutter, Expo, Android Requires Bachelors degree or higher in Computer Science or similar fields.
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Where this role is based

San Francisco, CA

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Helium headquarters

Company size

1–10 employees

Founded

2024

Total raised

$7,402,999

View company profile ↗

Funding rounds

  • Seed$5.4M
  • Pre Seed$2M