Full-Stack Product Engineer, AI Startup (Onsite)

Twenty80 llc; San Francisco (CA); On-site; USD 90,000 - 120,000; Full time

Job summary

Twenty80 llc is looking for a generalist product engineer in San Francisco. This role requires building full-stack features primarily using TypeScript, React, and Python. You'll be part of a small team, collaborating closely with product and design, while owning features from idea to production.

The ideal candidate has a CS or related STEM degree, 0 to 5 years of experience, and a proven track record of shipping user-facing products, ideally including AI-driven features. The position entails significant onsite work in a fast-paced environment.

Qualifications

• 0 to 5 years of experience in product engineering.
• Experience in building client-facing or consumer-facing products.
• Track record of shipping user-facing features end to end.

Responsibilities

• Build full-stack features across backend services, web apps, and mobile.
• Turn abstract product ideas into shipped features with minimal hand-holding.
• Collaborate with product, design, and go-to-market teams.

Skills

Full-stack development in TypeScript

React proficiency

Python knowledge

AWS familiarity

API design

Data modeling

Education

CS or related STEM degree (math, physics, EE, engineering)

Tools

Cursor

Claude

Job description

Twenty80 is representing a client building AI-powered products and looking for a generalist product engineer with 0 to 5 years of experience. This is a build-everything role on a small team. You will work across backend services, web, and mobile, and you will own features from idea to production. The common thread our client cares about is range and judgment, not a single specialty.

You use AI tooling well and you understand that generating code is the easy part. Planning, reviewing, and shipping quality software is where the real work lives, and you can explain every trade-off you made and why.

What you'll be doing

• Build full-stack features end to end across backend services, web apps, and mobile, primarily in TypeScript, React, and Python on AWS.
• Work across the whole product surface, where product engineering, AI features, and integrations blur together rather than sitting in separate lanes.
• Take abstract product ideas and turn them into shipped, client-facing features with minimal hand-holding.
• Collaborate in person with product, design, and go-to-market to iterate fast on what real users actually adopt.
• Dogfood the product and bring product intuition to the table, not just engineering execution.

Work experience

• Track record of building client-facing or consumer-facing products, at a startup or a strong tech company.
• Has shipped user-facing features end to end, ideally including AI or LLM-powered features.
• Clear upward trajectory in past roles. Promotions, expanded scope, a founding title, or obvious recognition.
• Comfortable in a fast-moving, scrappy environment where everyone touches infra, frontend, and everything between.

Education

CS or related STEM degree (math, physics, EE, engineering). A strong program is a plus, not a gate.

Hard skills

• Full-stack proficiency in TypeScript and React plus Python, on AWS.
• Solid backend fundamentals: API design, data models, SQL, and database work.
• Uses AI tooling like Cursor and Claude effectively, well beyond basic code generation, while still understanding the code underneath.
• Strong product intuition with real UX and UI sensibility.
• Mobile experience (React Native or similar) is a plus.

Soft skills

• Can articulate technical decisions and trade-offs clearly to non-technical people.
• High agency. Takes ownership and drives work to done without needing to be managed through it.
• Builds because they like building. Active GitHub, side projects, or a portfolio of hard technical work stands out.

Miscellaneous

• Must be authorized to work in the U.S.
• Onsite role based in San Francisco. You will work in person the majority of the week.