Andrew Tefft
Verified Expert in Engineering
Software Engineer and Developer
Maineville, OH, United States
Toptal member since June 1, 2026
Andrew is a staff software engineer with 15 years of experience building high-throughput back-end systems and ML infrastructure at Fox Corporation. He specializes in AWS serverless architecture, C#.NET back-end engineering, and MLOps, including recommendation systems and ML inference pipelines built on Amazon Personalize, SageMaker, and Databricks.
Portfolio
Experience
- C#.NET - 15 years
- REST APIs - 10 years
- AWS SDK - 8 years
- PySpark - 6 years
- AWS Step Functions - 6 years
- Machine Learning Operations (MLOps) - 6 years
- AWS Lambda - 6 years
- Claude Code - 1 year
Work Experience
Staff Software Engineer
Fox Corporation
- Designed and spearheaded the development of a personalized newsletter API delivering 2 – 3 million newsletters daily, sustaining 50,000 requests per minute on AWS serverless infrastructure.
- Developed an AI-powered editorial alerts API, automating personalized push notification generation with sports entity targeting.
- Architected a modernized push notification delivery system for the Fox Sports app, redesigning legacy infrastructure to improve scalability and observability.
Senior Software Engineer, MLOps
Fox Corporation
- Architected and developed an ML platform powering personalized content recommendations for multiple Fox business units, incorporating an A/B experimentation framework and MLOps orchestration for model training, deployment, and monitoring.
- Built and established an experimentation framework enabling per-surface A/B experiment configuration with pluggable business logic and self-service operational UI, shipped to production, powering Fox Nation recommendations.
- Served as technical lead within a cross-functional team of 13+, covering ML engineering, MLOps, experimentation, and platform engineering across data scientists, ML engineers, API engineers, and data engineers.
- Operated an ML platform supporting 15+ active models across 5+ personalized content recommendation surfaces, including similarity-based recommendations, continuous playback suggestions, and trending recommendations across Fox Nation and Fox Sports.
- Directed the migration of ML training and inference platform from AWS CloudFormation to Terraform over three months, serving as the primary driver across planning, implementation, and delivery.
- Deployed custom SageMaker models built by data scientists into the ML platform for production deployment and ongoing operations.
- Automated Amazon Personalize model lifecycle, including scheduled training pipelines, batch inference jobs, and live deployment with near real-time data ingestion.
- Deployed Fox's first personalized content recommendation system using PredictionIO and Elasticsearch on Amazon Elastic Compute Cloud (EC2), delivering Fox's initial personalized content experience to FOX Now streaming.
Software Engineer
Fox Corporation
- Focused on full-stack development for Fox Sports Fantasy Football from greenfield, delivering a public-facing product using C#.NET, HTML, CSS, JavaScript, and SQL.
- Built the Big Board, a real-time sports data display showing scores, stats, and schedules embedded across high-traffic foxsports.com pages, contributing to both back-end data services and front-end presentation.
- Contributed to the Sports Data platform, including 3rd-party data ingestion pipelines, SQL Server storage, and .NET middle-tier APIs supporting foxsports.com stats display pages.
Project History
Personalized Newsletter API
https://www.foxsports.com/newsletterMovie Semantic Search
https://github.com/atefft/movie-semantic-searchEducation
Bachelor's Degree in Computer Science
University of Cincinnati - Cincinnati, OH, USA
Skills
Libraries/APIs
REST APIs, PySpark, jQuery
Tools
AWS SDK, AWS Step Functions, Visual Studio, Git, Claude Code, Amazon Elastic MapReduce (EMR), Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Slack, Jira, Amazon SageMaker, GitHub Copilot, Terraform, AWS CloudFormation, Confluence, Amazon Elastic Container Registry (ECR), PredictionIO
Languages
C#.NET, C#, Python, SQL, Bash Script, XML, HTML, JavaScript, CSS, Java
Frameworks
.NET, Entity Framework Core, AWS Serverless Application Model (SAM)
Platforms
AWS Lambda, Windows, Visual Studio Code (VS Code), Amazon Web Services (AWS), Docker, Linux, Databricks
Paradigms
Agile Software Development, Event-driven Architecture, Object-oriented Programming (OOP)
Storage
Amazon S3 (AWS S3), Amazon DynamoDB, Redis, Elasticsearch
Other
Software Development, Amazon Personalize, Machine Learning Operations (MLOps), Systems Design, Back-end, SOLID Principles, Cursor AI, CI/CD Pipelines, MLeap, Amazon API Gateway, Amazon RDS, SQL Server, NVIDIA Triton, Qdrant, GitHub Actions, Data Engineering
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