Whatnot is the largest live 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, Germany, Ireland, and Poland, we’re building the future of online marketplaces –together.

From fashion, beauty, and electronics to 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.

💻 Role

Ads+Promos is a growing engineering team at Whatnot that is dedicated to building systems & features to help Sellers grow their business. As a software engineer on the Ads+Promos team, the most important qualities you'll need are making sound product decisions, navigating new domains seamlessly, taking extreme ownership, and shipping high-quality products fast. We always prioritize the highest impact features and ship them quickly. The software team has a lot of individual responsibility and many more freedoms, so we need to hire people we can trust. Your ability to put customers first, make good trade-offs and deliver impact is essential to us.

In this role, you will…

Architect, design, and lead the implementation of high-throughput, low-latency distributed systems that power ad delivery, ranking, signal pipelines, and attribution.
Own core foundational services (e.g., storage, attribution, streaming pipelines, APIs) and drive their evolution, performance tuning, resilience, and scalability.
Define and enforce architectural patterns, service contracts, fault-isolation, and capacity planning across teams that build on top of the Ads Foundation stack.
Lead cross-functional initiatives to integrate new ad features or experiments into the foundational layers without sacrificing performance or safety.
Mentor and guide senior engineers, lead code reviews, design reviews, and promote best practices in system design, testing, observability, and deployment.
Participate in incident response, root-cause analysis, and post-mortem processes for critical system failures.
Evangelize reliability, scalability, and simplicity across product-oriented ad teams; drive technical roadmap, trade-offs, and de-risking strategies.
Understand our buyer and seller experiences and become an expert in helping them effectively scale their business through ads & monetization products.

Team members in this role are required to be within commuting distance of our Kraków, Poland hub.

👋 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 Staff Software Engineer You Should Have

Bachelor’s degree in Computer Science, a related field, or equivalent work experience
8+ years (for Staff) or 10+ years (for Senior Staff) of backend/distributed systems engineering experience.
Strong mastery of distributed systems fundamentals: consensus, partitioning, replication, coordination, sharding, state management, etc.
Deep experience with high-throughput, low-latency services and stream processing (e.g., Kafka, Flink, etc.).
Strong software design, algorithmic, and data-structure skills.
Proficiency in one or more languages (e.g., Python, Go) and scripting.
Experience with messaging, caches (e.g., Redis, RocksDB), time-series stores, and data pipelines.
Proven track record of leading architecture and scaling core systems under high load, especially in an ads, ranking, or ML serving context.
Excellent communication skills, ability to influence cross-organizational stakeholders.
Proven track record of delivering features end-to-end and can ship products and features lightning-fast without sacrificing quality.
Strong ownership instincts — capable of driving projects from inception to production and beyond.
The ability to pick up on new technologies very quickly.
Startup experience at a high-growth company — working in fast-paced, rapidly evolving product environments with frequent experimentation (nice to have).
Experience with ads systems (bidding, auction, attribution, measurement, etc.), infrastructure, and international commerce (nice to have).

Please find our Whatnot Candidate Privacy Notice here.

💛 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.