Backend Engineer, Seller Growth

Whatnot is the largest livestream shopping platform in North America and Europe to buy, sell, and discover the things you love. We’re re-defining e-commerce by blending community, shopping, and entertainment into a community just for you. As a remote co-located team, we’re inspired by innovation and anchored in our values. With hubs in the US, UK, Ireland, Poland, and Germany, we’re building the future of online marketplaces—together.

From fashion, beauty, and electronics to rare collectibles like trading cards, comic books, and even live plants, our live auctions have something for everyone.

And we’re just getting started! As one of the fastest growing marketplaces, we’re looking for bold, forward-thinking problem solvers across all functional areas. 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.

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 Platform 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.

• Balancing growth with trust and safety: Ensuring that the thousands of new sellers joining weekly can sell successfully without degrading the buyer experience, while preventing bad actors from gaining distribution or abusing incentives.

• Building platform intelligence: Powering accurate seller identification (e.g., enrichment data, signals, and predictive LTV models) to route sellers to the right onboarding, incentive, and discovery paths.

• Creating scalable infrastructure: Partnering with Data Science and Trust teams to design reusable trust and reputation systems, modular fraud prevention frameworks, and experimentation platforms that other pods and teams across Whatnot can leverage.

• Driving long-term seller success: Enabling better bucketing of sellers by value and risk profile, ensuring that high-potential sellers are accelerated early, while low-quality or fraudulent sellers are contained before they reach scale.

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.

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

As our next Backend Engineer you should have 5+ years of software engineering experience , plus:

• Bachelor’s Degree in Computer Science or related field or equivalent work experience.

• Experience building scalable systems (we primarily use Python, Elixir, JavaScript).

• Ability to work across the stack (backend and frontend).

• Excellent product instincts. You first think about users rather than the best technical solution.

• Proven track record of delivering features. You are known for shipping products and features lightning-fast.

• Ability to take ownership of an ambiguous area and define and then drive impact.

• Ability to flexibly work across multiple workstreams, thriving in a fast-paced environment.

• Knowledge of data and growht systems like notifications.

• Scalability and data pipeline experience with SQL, dbt, etc.

• Flexible Time off Policy and Company-wide Holidays (including a spring and winter break)

• 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.

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.