Senior Machine Learning Engineer (Ads)

TL;DR

Senior Machine Learning Engineer (Ads): Developing foundational embedding models and signals for Reddit’s core entities with an accent on multimodal content understanding and behavioral relevance. Focus on building scalable ML pipelines, fine-tuning LLMs, and optimizing the ads delivery funnel through advanced representation learning.

Location: Must be based in the UK or the Netherlands

Company

Reddit is a massive community-driven platform connecting millions of users through shared interests and authentic conversations.

What you will do

• Develop and iterate on embedding models for advertising, including two-tower architectures and sequence models.
• Work with LLMs and VLMs to extract representations and perform fine-tuning for state-of-the-art performance.
• Build and maintain robust data processing and inference pipelines.
• Conduct end-to-end experimentation, from internal benchmarks to online A/B testing.
• Ensure system reliability, scalability, and performance through automated testing and monitoring.
• Collaborate with cross-functional teams to translate business requirements into technical ML solutions.

Requirements

• Must be based in the UK or the Netherlands
• 5+ years of hands-on experience with the full ML lifecycle.
• Proven experience building NLP or CV models at scale.
• Proficiency with PyTorch or TensorFlow.
• Experience developing complex features or embeddings for downstream models.

Nice to have

• Experience with the Reddit tech stack: Python, Airflow, BigQuery, Ray, k8s, kafka, GCP.
• Familiarity with the Ads domain, Search, or Recommender systems.
• Tech leadership experience and mentoring capabilities.
• Hands-on experience building or fine-tuning LLMs.

Culture & Benefits

• Global benefit programs including professional development and caregiving support.
• Private pension plan with employer matching.
• 100% employer-sponsored group medical plan.
• Flexible vacation policy and paid volunteer time off.
• Generous paid parental leave and family planning support.