Senior Machine Learning Engineer

Role: Senior Machine Learning EngineerLocation: St. Louis, MissouriDuration: 6+ Months
ONLY H1B Candidates and Local candidates are preferred ( Ready to relocate to Client location ) Min 10+ Years Exp Required
This is hybrid role in St. Louis, MO (2-3 days)
The Digital and eCommerce team currently operates several B2B websites and direct digital sales channels via a globally deployed cloud-based platform that are a growth engine for Client life science business. We provide a comprehensive catalog of all products, enabling our customers to find products and purchase products as well as get detailed scientific information on those products.
ESSENTIAL JOB FUNCTIONS

• Machine Learning Model Development: Design, train, and evaluate ranking models (learning-to-rank, neural networks, embedding-based approaches) to optimize search relevance and personalization.
• Search Query Analysis: Analyze search query logs, evaluate user behavior data to identify opportunities for relevance improvements and inform ranking strategies.
• Feature Engineering: Develop and engineer features from search, product, and user data to power ML models and improve ranking performance.
• Semantic Search & NLP: Implement semantic search for improved product discovery across chemistry and life science domains.
• Search Engine Tuning: Optimize Elasticsearch/Lucene configurations, including tokenization, stemming, query parsing, and lexical search algorithms (BM25) to work in concert with ML models.
• ML Pipeline Development: Build and maintain end-to-end ML pipelines, including data preprocessing, feature engineering, model training, evaluation, and deployment using MLOps best practices.
• Ranking & Personalization: Develop personalized ranking strategies that adapt to user segments, query intent, and business objectives; integrate collaborative filtering and content-based approaches.
• Performance Monitoring & Iteration: Monitor search and ML model performance metrics in production; identify drift and continuously improve models based on new data and domain insights.
• Search Relevance Documentation: Maintain clear documentation of search algorithms, ranking models, tuning strategies, and system configurations for internal teams.
• Mentorship: Guide engineers on search relevance techniques, ML best practices, and data-driven problem-solving.

QUALIFICATIONS
Education:

• Bachelor’s degree in Computer Science, Engineering, Data Science, or a related quantitative field.

Mandatory Skills:

• 6+ years of hands-on experience in machine learning, data science, search relevance, or ranking systems.
• Proven expertise in Python and ML frameworks (TensorFlow, PyTorch, Scikit-learn, or equivalent).
• Strong background in statistical analysis, data exploration, and working with large-scale datasets.
• Experience with feature engineering, data preprocessing, and data manipulation libraries (Pandas, NumPy, Spark).
• Demonstrated experience building or working with ranking models (learning-to-rank, neural ranking, or similar).
• Experience with semantic search, embeddings, or dense retrieval methods.
• Deep understanding of search engines (Elasticsearch, Solr, OpenSearch), lexical search algorithms (BM25), information retrieval concepts, search relevance tuning, tokenization, stemming, and query parsing.
• Experience with MLOps practices and tools (model versioning, experiment tracking, pipeline orchestration).
• Proficiency in SQL and querying large datasets.
• Strong problem-solving and analytical skills with the ability to think critically about complex search and ranking problems.
• Excellent communication skills; ability to explain ML and search concepts to both technical and non-technical stakeholders.
• Ability to collaborate with cross-functional teams