Machine Learning Engineer

Adxe is a global company developing an AI-powered programmatic DSP platform that processes millions of bid requests per second across ad exchanges including Xandr, Google, Pubmatic, OpenX, and Index. We serve clients in gaming, fintech, e-commerce, and enterprise verticals.

We are looking for a Machine Learning Engineer to join our ML team. This role offers flexible working arrangements—consulting, part-time, or full-time—with a fully remote work model.

What You'll Do

• Build and improve our CTR prediction models using LightGBM for real-time bidding decisions

• Work with our 13-step bid processing pipeline and tree-based targeting index (163+ dimensions)

• Research and optimize feature engineering using Polars for high-performance data processing

• Deploy model artifacts to S3 with hot-reload capabilities to the bidder cluster

• Extract and engineer 26+ features from OpenRTB bid requests for model training

• Collaborate with backend engineers to optimize ML inference latency (<100ms response time)

Required Experience

• Proven experience with gradient boosting frameworks (LightGBM, XGBoost, CatBoost) in production

• Strong Python skills with experience in Polars or Pandas for feature engineering

• Experience with recommendation systems (RecSys) and CTR/CVR prediction

• Knowledge of binary classification models and evaluation metrics (AUC, log-loss)

• Familiarity with Papermill or similar notebook parameterization tools

• High level of proficiency in English

• Proactive, highly motivated individual with strong work ethic and sense of ownership

Nice to Have

• Experience in ad-tech, RTB systems, or programmatic advertising

• Familiarity with OpenRTB protocol and bid request/response structures

• Experience with ClickHouse for analytics data extraction

• Knowledge of Two Tower Models and deep learning approaches for RecSys