Fullstack Engineer, Seller Growth at Whatnot in San Francisco, CA

🚀 Join the Future of Commerce with Whatnot!

Whatnot is the largest livestream shopping platform in North America and Europe to buy, sell, and discover the things you love. Whether it's trading cards, fashion, electronics, or live plants, our sellers are building real businesses across hundreds of categories. We're building live commerce at a scale that's never been done in the West, and there's no playbook to copy. The people here are shaping how an entirely new industry develops.

As a remote co-located team, we're inspired by our values and anchored in hubs across the US, UK, Ireland, Poland, Germany, and Australia. We move fast, stay close to our users, and focus on the work that drives the most impact.

We're one of the fastest growing marketplaces and were recently named the #1 Best Startup Employer in America by Forbes. Check out the latest Whatnot updates on our news and engineering blogs and join us as we enable anyone to turn their passion into a business and bring people together through commerce.

💻 Role

Seller Growth is responsible for growing sellers on Whatnot — enabling them to turn their hobbies into businesses. Within Seller Growth, the Platform pod ensures that this growth is sustainable, trustworthy, and scalable.

As our next software engineer on the Seller Growth Product pod, you will design and build the systems that sit at the heart of the new seller funnel. Your work will focus on:

• Protecting the funnel from fraud and abuse: Developing and scaling systems for identity verification (IDV), fraud detection, and automated trust/risk reviews that safeguard buyers while minimizing friction for good sellers.

• Ship seller-facing experiences: Deliver features across onboarding, education, and seller incentive flows — working across the full stack (backend and frontend).

• Build platform intelligence: Develop seller enrichment pipelines and signals to route sellers to the right onboarding, incentive, and discovery paths.

• Drive growth through experimentation: Design and analyze A/B tests to guide product decisions and accelerate seller success.

• Create scalable infrastructure: Build and maintain data pipelines and growth systems (e.g., notifications, lifecycle triggers) that other pods and teams can leverage.

This pod works at the intersection of growth, trust, and platform-ization. You’ll be responsible for deeply technical systems (IDV, fraud signal repositories, seller enrichment pipelines, predictive models) that directly influence GMV, seller retention, and buyer trust. The pace is fast: every week, thousands of sellers apply to sell, and your work ensures that Whatnot can confidently scale this influx without compromising marketplace integrity.

👋 You

Curious about who thrives at Whatnot? We’ve found that embodying a low ego, growth mindset, and high-impact drive goes a long way here.

As our next Fullstack Engineer, you should have (e.g. 3+ years of generalist software development experience in high growth startups), plus:

• Bachelor’s degree in Computer Science, a related field, or equivalent work experience

• Knowledge of multiple programming languages (we primarily use Python, Elixir, JavaScript—knowledge of these in particular not required)

• Web development experience with React, using GraphQL for API development, and modern frontend applications (exposure to Next.js framework is not required but preferred)

• Excellent product instincts—you first think about users rather than the best technical solution

• You can mentor others, and prioritize building inclusive, supportive teams

• Project owner—you’ve strong ownership instincts and can own projects from inception to production and beyond

• You are known for shipping products and features lightning-fast

• You’re an excellent problem solver and can operate autonomously

• Ability to pick up on new technologies very quickly

• Proven track record of delivering features

🎁 Benefits

• Generous Holiday and Time off Policy

• Health Insurance options including Medical, Dental, Vision

• Work From Home Support

  • Home office setup allowance

  • Monthly allowance for cell phone and internet

• Care benefits

  • Monthly allowance for wellness

  • Annual allowance towards Childcare

  • Lifetime benefit for family planning, such as adoption or fertility expenses

• Retirement; 401k offering for Traditional and Roth accounts in the US (employer match up to 4% of base salary) and Pension plans internationally

• Monthly allowance to dogfood the app

  • All Whatnauts are expected to develop a deep understanding of our product. We're passionate about building the best user experience, and all employees are expected to use Whatnot as both a buyer and a seller as part of their job (our dogfooding budget makes this fun and easy!).

• Parental Leave

  • 16 weeks of paid parental leave + one month gradual return to work *company leave allowances run concurrently with country leave requirements which take precedence

💛 EOE

Whatnot is proud to be an Equal Opportunity Employer. We value diversity, and we do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, parental status, disability status, or any other status protected by local law. We believe that our work is better and our company culture is improved when we encourage, support, and respect the different skills and experiences represented within our workforce.