# Stephanie Marker

> Senior Software Engineer at Klaviyo

Location: Salem, New Hampshire, United States
Profile: https://flows.cv/stephaniemarker

Senior software engineer seeking a lead role at a smaller startup that needs someone who can improve system reliability, scalability, and performance from day one. I have experience building at both extremes from production systems at Microsoft with global impact to fast-paced, high-ownership work in a startup of fewer than 40 engineers at Embark Veterinary.

I bring broad experience across backend engineering, distributed systems, cloud infrastructure, and data pipelines. I’ve led projects, stabilized production environments, mentored teammates, and delivered systems that scale.

Comfortable with Python, TypeScript, AWS, Kubernetes, Terraform, PostgreSQL/Redis, event-driven patterns, and ML/data tooling.

I enjoy turning complex requirements into simple, reliable, and scalable solutions. I care about building systems that reduce operational friction, support business growth, and create great user experiences.

## Work Experience
### Senior Software Engineer - Billing Usage, Billing Plans & Payments @ Klaviyo
Jan 2024 – Present | Boston, Massachusetts, United States
Leading and contributing to several critical initiatives aimed at improving billing system reliability, scalability, and customer trust.

Key Contributions:

- Architected scalable side effects system managing transient database tasks with cron-based execution engine, supporting immediate/delayed actions with team-configurable monitoring; adopted by 10+ product teams with 20+ registered side effects to orchestrate feature access changes on access-based events.
- Created enterprise-scale free trial infrastructure with Django APIs serving 4 products, handling 1M+ requests/sec and 50k+ concurrent users with Redis ElastiCache and Aurora RDS, contributing to a 15% conversion rate lift and accelerating sales acquisition.
- Built scalable usage threshold and payment notification system with a config-driven approach, eliminating existing product-specific boilerplate classes and reducing code maintenance overhead while providing automated notifications for payment success/failure events and usage threshold limits reached across products.
- Designed and deployed a real-time Stripe webhook processing system with automated billing plan discrepancy detection and distributed tracing, eliminating plan mismatches and reducing incident resolution time by 50%.
- Scaled billing Memcached infrastructure and implemented Splunk cron job monitoring alerts to maintain 100% billing uptime during 5x Black Friday traffic surge.
- Delivered UK VAT compliance system within critical Black Friday/Cyber Monday deadline, enabling significant monthly revenue expansion.

### Senior Software Engineer - Customer Experience Team @ Embark Veterinary
Jan 2024 – Jan 2024 | Boston, Massachusetts, United States
Shipped customer-facing genetic report features used by 2M+ pet owners using React/TypeScript and GraphQL APIs, surfacing complex genomic insights across health, traits, and ancestry through intuitive UX.

### Senior Software Engineer - Scientific Computing Team @ Embark Veterinary
Jan 2021 – Jan 2024 | Boston, MA
- Identified and led a cost-optimization initiative that led to $180K+ annual cost savings (10% monthly reduction) by AWS resource rightsizing and tagging, autoscaling, and proactive Cloudwatch monitoring.
- Extended ML deployment infrastructure for Embark's dog DNA testing product by implementing Apache Airflow workflows for new ML models including the productionized Mast Cell Tumor (MCT) ML model, processing 120K+ genetic assessments/month and ~6k DNA samples/day with 99.99% uptime.
- Led productionization of Embark's Dog Age Test by researching scientific literature and recommending preprocessing optimizations to scientists, then transforming experimental Jupyter notebooks into a production Python package using NumPy vectorized operations on DNA methylation data, reducing ML feature deployment time from months to weeks following scientific advisory board review.
- Designed domain-driven PostgreSQL schemas for Illumina sequencing workflows, improving data consistency by 30% and enabling cross-functional genetic research at scale.
- Partnered with 10+ veterinarians and geneticists to validate and release health and trait algorithms, expanding available genetic insights to 250+ total while ensuring accurate genome data storage and UI presentation.

### Software Engineer II - Intune Product, Apple VPP Team @ Microsoft
Jan 2020 – Jan 2021 | Cambridge, Massachusetts, United States
- Built and maintained production-scale C# microservices for Microsoft Intune, enabling secure mobile device management of apps on iOS and macOS across global enterprise and educational customers.
- Architected and co-owned critical microservices integrating Apple's Volume Purchase Program API, managing license counts in CosmosDB to streamline app deployment and license management worldwide.
- Led deprecation and removal of an outdated data provider, saving a DB migration and reducing codebase complexity and enhancing maintainability for the engineering team.

### Software Engineer I & II - Commercial Software Engineering Team @ Microsoft
Jan 2017 – Jan 2020 | Cambridge, Massachusetts
- Authored the Microsoft blog article, “Deploying a Batch AI Cluster for Distributed Deep Model Training”, sharing best practices with the broader engineering community.
- Architected scalable distributed ML training infrastructure on Azure Batch AI using Keras, TensorFlow, and Horovod, enabling multi-node model training for satellite image classification processing thousands of images identifying sustainable farming practices.
- Designed and implemented an advanced signal processing pipeline in R for clinical research (Project Fizzyo), developing a custom peak detection algorithm that improved pattern analysis accuracy for cystic fibrosis treatment optimization.
- Delivered React-based administrative dashboard for Fortis, a UN crisis response platform, enabling real-time sentiment analysis and media aggregation across multiple channels during humanitarian emergencies.

### Senior IT Data Analytics Analyst @ UnitedHealth Group
Jan 2016 – Jan 2017 | Basking Ridge
- Developed JCL Parser for Hadoop: Built a Java-based JCL parser running on Hadoop to efficiently process thousands of JCL files, extracting important metadata to diagram out relationships between our systems in an angular web UI.
- Predictive Analytics: Applied multivariate regression in Python to predict service response times based on daily transactions, achieving over 80% accuracy and providing valuable insights for system optimization.
- Hackathon Winner: Led a winning team in a company-wide hackathon (over 25 teams) by developing a Rails application that facilitated communication of company-specific technical questions among developers at UHG.

### Senior Technology Development Program Associate @ UnitedHealth Group
Jan 2015 – Jan 2016 | Basking Ridge, New Jersey
- Led Frontend Team for UHG Angular Web App: Led a team of 6 developers to create an Angular-based web app that visualized relationships between programs at UHG, while also contributing to backend Java Spring services that pulled data from ElasticSearch.
- Machine Learning Contest Winner: Led a team to 1st place out of 65 teams in a UHG machine learning contest, presenting a pitch to executive judges aimed at increasing member outreach and net promoter scores (NPS).
- Created Shell Scripts for Data Consistency: Developed shell scripts to verify data consistency between Hive ORC tables and ElasticSearch.

### CS111 Recitation Instructor @ Rutgers University
Jan 2014 – Jan 2015
- Taught Java Concepts: Led weekly sections for over 10 students, teaching core Java programming concepts and helping them build a strong foundation in software development.
- Graded Projects and Provided Support: Graded final coding projects, offering constructive feedback and additional assistance to students on their assignments and projects to ensure understanding and progress.

### Optum Technology Intern @ UnitedHealth Group
Jan 2014 – Jan 2014 | Basking Ridge, NJ
- Developed a Dynamic Web App for UHG Basking Ridge Office: Collaborated with a 12-person team to create a dynamic web application that improved user office navigation.
- Created Shortest Path Algorithm: Designed and implemented an algorithm in JavaScript to calculate the shortest path from a user’s current location to their destination, streamlining the navigation process for users.


## Education
### Bachelor of Science (B.S.) in Mathematics and Computer Science
Rutgers University
Jan 2011 – Jan 2015


## Contact & Social
- LinkedIn: https://linkedin.com/in/stephaniemarker
- Website: https://www.stephaniemarker.com
- GitHub: https://github.com/Smarker
- Website: https://www.cheapquickvegan.com

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Source: https://flows.cv/stephaniemarker
JSON Resume: https://flows.cv/stephaniemarker/resume.json
Last updated: 2026-03-22