Arena Club
Senior Machine Learning Engineer, Recommendations
San Francisco, CA · Senior
Sponsorship not specified$170k-$230kDetected 7 days ago
PythonSQLElasticsearchVector DatabasesAWSMachine LearningTensorFlowPyTorchscikit-learnData EngineeringData ScienceNLPMLOpsStatisticsA/B TestingPlain Language
About the role
- This is production machine learning in the request path, where model quality translates directly into conversion, engagement, and revenue.
- The mandate covers the full lifecycle: taking a ranking approach from concept through deployment, monitoring, and continuous iteration, then validating each improvement in rigorous controlled experiments.
- Impact here is measured not by models shipped but by demonstrable lift in the metrics that move the business.
Responsibilities
- Design, train, and deploy recommendation and ranking models that improve relevance and conversion across the marketplace
- Own a recommendation and search index that beats a strong third-party control on conversion and cuts fallback rates
- Build homepage, onboarding, and category-level personalization ranking
- Develop retrieval and candidate-generation systems using embeddings and semantic search
- Own the full ML lifecycle: data ingestion, feature engineering, training, evaluation, deployment, monitoring, and iteration
- Deploy and operate low-latency inference in the request path, and design scalable systems for serving and pipeline execution
- Build and maintain batch and near-real-time data pipelines using Python and PySpark
- Collaborate with backend engineers to integrate models into customer-facing systems
- Partner with Product, Engineering, and the marketplace squad to translate high-level needs into technical problem statements
- Design and interpret A/B tests to validate model and product changes
Requirements
- 5+ years in applied ML or ML engineering, with a track record of shipping models to production in a consumer-facing environment
- Expert-level proficiency in Python and the ML ecosystem (PyTorch, TensorFlow, Scikit-learn)
- Experience applying ML to user behavior data (clickstream, transactional, event logs)
- Comfort with experimentation (A/B testing, lift measurement, business impact interpretation)
- Knowledge of MLFlow or an equivalent experiment-tracking and model-registry tool
- Bachelor's degree in Computer Science, Statistics, Mathematics, or a related quantitative field; advanced degree preferred
- 3+ years building recommendation, ranking, search relevance, or personalization systems
- Experience with learning-to-rank, embeddings, retrieval, and semantic search
- Advanced SQL for complex data extraction and processing.
- Strong AWS experience (EC2, S3, and related services) for model hosting and data workflows
Nice to have
- Experience with AWS OpenSearch, Algolia, or other search and retrieval systems
- Experience with Marketplace recommendation system modeling
- Experience with vector databases and approximate nearest-neighbor search
- NLP experience, including embeddings, text classification, or semantic search
- The Arena Club Standard
- Deploy and operate ML workloads on AWS (EC2, S3, and related services)
- Improve reproducibility, experiment tracking, and observability across the stack
- Communicate model behavior, trade-offs, and timelines in plain language to non-technical stakeholders
Compensation
- $170,000 - $230,000 USD
- The base salary range listed is a guideline.
Benefits
- Total compensation includes base salary, bonus, and equity.
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