Staff ML Engineer, Ads Platform & Real-Time Bidding

Whatnot; Kraków; On-site; PLN 911,000 - 1,116,000; Full time

Benefits offered by this job

Holiday and time off

Health Insurance

Work from home support

Home office setup

Internet allowance

Childcare support

Retirement plans

Parental leave

Job summary

Whatnot in Kraków is hiring a Staff Machine Learning Engineer, Ads to shape the engineering foundation of our advertising marketplace on site in Kraków. You will design high-throughput, low-latency backend systems powering ad auctions, bidding, pacing, ranking, and delivery, collaborating with product, ML, and infra teams.

You will own architecture decisions, lead end-to-end features, and mentor engineers while delivering scalable solutions for a global marketplace.

Qualifications

• Bachelor’s degree or equivalent experience; 8+ yrs Staff or 10+ yrs Senior Staff in backend/distributed systems.
• Strong fundamentals in consensus, partitioning, replication, coordination and sharding.
• Deep experience with high-throughput, low-latency services and stream processing.
• Proficient in Python or Go and scripting.
• Experience with messaging, caches, time-series stores, and data pipelines.
• Proven architecture leadership for ads/ranking/ML serving contexts.

Responsibilities

• Architect and lead high-throughput backend systems powering ad auctions and ranking.
• Design mechanisms balancing seller value, buyer experience, and marketplace efficiency.
• Develop services for budget management, forecasting, and measurement.
• Integrate real-time auction services with ML models and data pipelines.
• Own performance, resilience, and observability of critical services.
• Drive architectural decisions and capacity planning across teams.
• Lead technical reviews, mentor engineers, and raise engineering bar.
• Collaborate with product, ML, and infra teams to ship fast with quality.

Skills

Distributed systems

Low latency

Backend design

Python

Go

Messaging

Data pipelines

Communication

Leadership

Education

BSc in CS or related field

Tools

Kafka

Flink

Redis

RocksDB

Job description

Whatnot in Kraków is hiring a Staff Machine Learning Engineer, Ads to shape the engineering foundation of our advertising marketplace on site in Kraków. You will design high-throughput, low-latency backend systems powering ad auctions, bidding, pacing, ranking, and delivery, collaborating with product, ML, and infra teams.

You will own architecture decisions, lead end-to-end features, and mentor engineers while delivering scalable solutions for a global marketplace.