Senior Machine Learning Engineer, Ads Foundational Representations

• Work on the Ads Foundational Representations team developing signals and representations of Reddit's core entities, capturing semantic, contextual, and behavioural information that Reddit Ads needs. • Build embeddings to understand content and users' interests based on the content they engage with, highlighting Reddit's genuinely curated, high-quality organic content. • Be in charge of the full-cycle execution of ML projects, from collaborating with cross-functional teams on requirements and design to implementation and experimentation.

• Bring 5+ years of hands-on experience with the full lifecycle of designing, training, evaluating, testing, and deploying industry-level models. • Have experience building NLP or CV models and integrating them at scale. • Have experience developing complex features and embeddings for downstream models. • Bring experience with mainstream deep learning frameworks such as PyTorch or TensorFlow. • Be excited about working with data and ready to look behind the metric numbers.

• Have experience with the stack including Python, PyTorch, Airflow, BigQuery, Ray, Kubernetes, Kafka, and GCP. • Bring familiarity with the Ads domain and/or Search or Recommender systems. • Have tech leadership experience mentoring junior engineers and leading complex projects. • Bring hands-on experience with using, fine-tuning, or building LLMs.

• Develop new or iterate on existing embedding models for advertising use cases, ranging from aggregation pipelines to two-tower architectures and sequence models. • Work with local and third-party LLMs and VLMs to extract representations, develop evaluation methodologies, prompt-tune and fine-tune large models to build state-of-the-art embeddings. • Build data processing and inference pipelines for the models developed. • Perform qualitative and quantitative evaluation of features, running end-to-end experimentation from internal benchmarks to downstream recommender system offline metrics to online experiments. • Ensure the reliability, scalability, and performance of ML systems by writing automated tests, monitoring performance, and implementing best practices for model management. • Participate in modelling and coding reviews, providing feedback to ensure team standards for quality and performance. • Collaborate with cross-functional teams to understand business requirements and translate them into technical solutions.

• Access global benefit programmes that fit your lifestyle, from workspace to professional development to caregiving support. • Receive family planning support. • Access gender-affirming care. • Use mental health and coaching benefits. • Join the Group Personal Pension Scheme with employer match. • Access private medical and dental scheme. • Benefit from income replacement programmes. • Use the Bike to Work scheme. • Enjoy flexible vacation and paid volunteer time off. • Take generous paid parental leave.

Reddit is a community of communities, home to the most open and authentic conversations on the internet. With 100,000+ active communities and approximately 130 million daily active unique visitors, Reddit is one of the internet's largest sources of information. Every day, users submit, vote, and comment on the topics they care most about.