Software Engineer, Ads

Whatnot Inc.; Kraków; Hybrid; PLN 200,000 - 360,000; Full time

Job summary

Whatnot Inc. is seeking a Backend Engineer for the Ads team to build end-to-end backend services across the ads stack, including bidding, targeting, and campaign management.

You will own end-to-end problems, ship high-quality features, and help sellers grow their businesses on a rapidly expanding live-commerce platform. You should bring 4+ years of production backend experience, a strong sense of tradeoffs between speed and reliability, and excellent collaboration skills with product, design,

Qualifications

• Bachelor’s degree in Computer Science, a related field, or equivalent practical experience.
• 4+ years of professional software engineering experience building and shipping backend systems in production environments.
• Strong experience designing, building, and operating scalable, maintainable backend services.
• Strong technical judgment and the ability to make thoughtful tradeoffs between speed, quality, reliability, and long-term maintainability.
• Experience working in fast-moving, cross-functional product or platform environments.
• Comfort owning ambiguous problem spaces and turning them into clear technical plans and shipped outcomes.
• Strong communication and collaboration skills, especially when partnering across engineering, product, design, and data.
• A product‑minded approach to engineering — you care not just about whether a system works, but whether it creates value for users and partner teams.

Responsibilities

• Build ads backend services end-to-end across the full ads stack (bidding, targeting, ranking, serving, campaign management and seller tooling).
• Develop highly scalable ads systems handling all aspects of running an online advertising platform and help sellers differentiate themselves.
• Dive into data, logging, and system behavior to reason about performance, correctness, and impact, not just shipping features.
• Understand buyer and seller experiences and enable them to scale their business through ads products.

Skills

Backend engineering

Distributed systems

APIs

SQL/NoSQL databases

Cloud services

Education

Bachelor's degree in Computer Science or related field

Job description

Join the Future of Commerce with Whatnot!

Whatnot is the largest live 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

Ads is a growing engineering team at Whatnot dedicated to building systems & features to help Sellers grow their business. As a software engineer on the Ads 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.

We're hiring across the full ads stack — from engineers who go deep on backend systems and data to engineers who move fluidly across the stack into client and seller-facing surfaces. In either case, you'll own problems end to end and grow into new areas as the team scales.

• Build ads products by working across the full ads stack including bidding & targeting, ranking/auction, serving, campaign management, and seller tooling.

• Build highly scalable ads systems that handle all aspects of running an online advertising system and help sellers differentiate themselves on Whatnot.

• Dig deep into data, logging, and system behavior to reason about performance, correctness, and impact — not just ship features, but understand why they work.

• Understand our buyer and seller experiences and become an expert in helping them effectively scale their business through ads products.

You

People who do well at Whatnot tend to be comfortable figuring things out as they go, biased toward action, and genuinely curious about what they're building. They care more about outcomes than credit and stay close to the product and the people using it.

As our next Backend Engineer you should have:

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

• 4+ years of professional software engineering experience building and shipping backend systems in production environments.

• Strong experience designing, building, and operating scalable, maintainable backend services.

• Strong technical judgment and the ability to make thoughtful tradeoffs between speed, quality, reliability, and long-term maintainability.

• Experience working in fast-moving, cross-functional product or platform environments.

• Comfort owning ambiguous problem spaces and turning them into clear technical plans and shipped outcomes.

• Strong communication and collaboration skills, especially when partnering across engineering, product, design, and data.

• A product‑minded approach to engineering — you care not just about whether a system works, but whether it creates value for users and partner teams.

Please note: Whatnot will only contact you through official @whatnot.com email addresses. If you see an email impersonating a Whatnot recruiter, please disregard and report it as spam.

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.