Machine Learning Engineer (Search Ranking)

Location: Belgrade, Berlin, or London

Company

Perplexity develops an AI-powered search product.

What you will do

• Improve search quality across the middle and later stages of ranking.
• Own ranking-quality problems end to end, from evaluation and bottleneck identification through implementation and safe release.
• Train and evaluate retrieval, ranking, and classification models, including neural and LLM-based approaches.
• Build and operate ranking infrastructure for feature computation, low-latency inference, multi-stage cascades, deployment, and monitoring.
• Balance quality, latency, reliability, cost, and engineering complexity.
• Collaborate with Data, AI, Infrastructure, and Product while owning the final quality outcome.

Requirements

• Deep understanding of search or recommender systems and their evaluation.
• Proven ownership of a large-scale production ranking system or substantial quality problems.
• Strong machine-learning and software-engineering skills across data, models, serving, and monitoring.
• Ability to drive ambiguous, cross-team problems independently.
• Exceptional depth in modern neural ranking methods or low-latency ranking systems and runtime.
• At least 5 years of relevant industry experience.

Culture & Benefits

• Full-time role in the Search department.
• Cross-functional collaboration across Data, AI, Infrastructure, and Product.