Wei Zhang
Machine Learning Engineer · San Jose, CA
Summary
ML engineer with 7 years building and deploying ranking and forecasting models in production. Owns the training and serving stack for a recommender handling 30M daily requests at p99 under 80 ms, and lifted click-through rate by 9% in A/B testing after moving to a two-tower retrieval model.
Experience
Machine Learning Engineer, Parcelwise Technologies
Mar 2022 – Present
San Jose, CA
- Built a two-tower retrieval and gradient-boosted ranking pipeline in PyTorch and XGBoost, serving 30M requests a day and lifting click-through rate by 9% in a 4-week A/B test.
- Moved model serving from a batch job to a Kubernetes-hosted service on Triton, bringing p99 latency from 310 ms to 78 ms while cutting GPU spend by 35%.
- Created a feature store on Feast and Spark with point-in-time correct training sets, removing a train-serve skew that had inflated offline AUC by 0.04.
- Set up MLflow tracking, automated retraining in Airflow and drift monitoring in Evidently, catching 3 data-quality incidents before they reached users.
Data Scientist, Machine Learning, Meridian Logistics Analytics
Jul 2019 – Feb 2022
Sacramento, CA
- Developed demand forecasting models in LightGBM and Prophet for 2,400 SKUs, improving weekly WAPE from 31% to 22% and reducing stockouts by 14%.
- Trained a computer vision model on 120,000 labeled images with a ResNet backbone to flag damaged parcels, reaching 94% recall at 91% precision.
- Packaged models in Docker and deployed them to AWS SageMaker endpoints with CI checks, taking release time from 2 weeks to 2 days.
- Partnered with product and operations on experiment design, running 11 A/B tests with power analysis and guardrail metrics.
Skills
Python · PyTorch · XGBoost / LightGBM · scikit-learn · Feature stores (Feast) · MLflow and experiment tracking · Airflow · Spark / SQL · Docker and Kubernetes · Model serving (Triton, SageMaker) · A/B testing and experiment design · Model monitoring and drift detection
Education
M.S. in Computer Science (Machine Learning), University of California, San Diego, 2019
Certifications
- AWS Certified Machine Learning Engineer - Associate
- TensorFlow Developer Certificate