Senior Backend Engineer, Ads Platform (Remote)

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

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,