Wilson K. Choi

Built Model Packaging & Deployment pipeline, bridging the gap between Data Science and Engineering.

• Pipeline Architecture: Designed a CI/CD workflow (Jenkins + Python) that automates scikit-learn ML model validation, packaging, registration, load testing, and deployment to AWS SageMaker for real-time and batch inference.
• Reliability & Observability: Integrated SageMaker Inference Recommender for load testing and built custom dashboards in Grafana/ELK to monitor model performance and endpoint health.
• Process Improvement: Introduced "Nightly Builds" with synthetic test data (Parquet/Joblib), ensuring the deployment pipeline and model artifacts were production-ready, reducing deployment failures.

Embedded across multiple teams as a technical resource to deliver new products, address system performance issues, and establish operational standards.

• Push Verify: Built a gRPC-based push notification verification service (Python, RabbitMQ, Firebase FCM) with multi-region deployment, operational runbooks, and Grafana/ELK monitoring.
• Score Architecture: Optimized latency of the Score pipeline and contributed to the Score 2.0 architecture redesign, improving the model serving layer for the fraud detection platform.
• Email Cleansing: Developed a Python library for email validation and normalization using Parsing Expression Grammar (PEG), supporting RFC 5322 compliance plus provider-specific rules (Google, Yahoo, Outlook).

Architected and built the "Voice CPaaS" platform ("Vox"), transforming a legacy VoIP stack into the company's primary revenue engine.

• System Rebuild: Migrated a legacy Asterisk stack to FreeSwitch, Kamailio, and FastAPI running on-prem and AWS, enabling features including IVR, Text-to-Speech, Conference Bridging, and Automated Speech Recognition (ASR) for enterprise customers including Microsoft Azure.
• Scaling & Availability: Designed a VoIP architecture and scaled platform capacity from 50 to 300 new calls per second (CPS) while maintaining 99.99% availability across US, EU, and Asia data centers.
• Hybrid Cloud & Call Recording: Engineered a hybrid architecture integrating on-premise telephony (FreeSwitch, Kamailio, UniMRCP) with AWS (Polly, S3, CloudFront, SQS, DynamoDB) and GCP (Speech-to-Text). Designed end-to-end Call Recording & Transcription pipeline (FreeSwitch → S3 → Transcription → customer-facing API).

Led a squad of 4 engineers building high-volume fraud detection APIs. Served as both Technical Lead and People Manager.

• Performance Engineering: Reduced Risk Scoring API latency from 300ms to 50ms (-83%) by optimizing data retrieval logic and implementing a multi-layer caching strategy.
• Data Pipeline: Managed the ETL pipeline processing millions of daily transactions, serving as the backbone for the company's "Phone Number Intelligence" product.
• Leadership: Mentored team members, conducted performance reviews, and managed product architecture planning. Delivered the "Batch Scoring Processor," which unlocked a new enterprise customer segment.

• Internal Tools: Built centralized dashboards (Django) to manage API features, BI reporting, customer configurations, and billing/invoicing (NetSuite integration).
• Data Warehouse: Collaborated with DBAs to design and implement OLTP/OLAP systems and ETL processes, improving reporting capabilities for the sales and support teams.

Early engineering hire (#50); company grew from startup to 700+ employee global enterprise during tenure.

• High-Throughput Messaging: Implemented asynchronous queuing systems using Python Celery and Redis, resolving critical bottlenecks in SMS transaction processing.
• Gateway Integration: Integrated backend systems with Kannel (Open Source WAP/SMS gateway) to expand carrier connectivity.
• Distributed Systems: Refactored the monolithic backend to support distributed compute requirements, migrating from a single data center to a multi-region (3 DC) architecture.