Jeff Brennan

senior data engineer

I’m a data engineer with a background in public health, motivated by better care for underserved communities. I build reliable data platforms, improve performance, and make working with data easier through thoughtful tooling and mentorship.

At Astrana Health, my work spans a shared Databricks platform, patient matching at a scale of 6.5 million patients, and APIs that bring claims and quality data to care teams. I also contribute to open source and build developer tools, including sparkparse, a parser that helps diagnose Spark performance problems.

Resume

Skills

  • Development: Python, SQL, R; agentic engineering (coding agents, reusable skills)
  • Data platforms: Databricks, Apache Spark, PySpark, Delta Lake, Unity Catalog
  • Cloud: Azure, Azure Data Lake Storage Gen2 (ADLS Gen2)
  • Infrastructure as code: Databricks Asset Bundles, Terraform
  • Delivery and testing: Azure DevOps, CI/CD, Docker, pytest, Pydantic
  • Pipelines: Azure Data Factory, Databricks Jobs, ETL, ELT, change data capture (CDC)
  • Data modeling and APIs: PostgreSQL, GraphQL, Databricks Apps, Svelte
  • Analytics and visualization: Power BI, Tableau, Plotly Dash, data visualization
  • Healthcare data: HIPAA, PHI, Epic Clarity, claims, HL7, CCDA, CMS CCLF
  • Certifications: Databricks Data Engineer Professional, Epic Clinical Data Model

Experience

Senior Data Engineer at Astrana Health
Jul 2025 - Present
  • Automated Databricks app, dashboard, and materialized view releases with Azure DevOps CI/CD, enabling 18 people to deploy without production administrator access
  • Built a Splink patient identity platform resolving 6.5M patients across 23 source systems, preserving a 91M-record auditable match history
  • Developed incremental PostgreSQL sync and GraphQL APIs for 20+ clinical data models, serving applications across 64 physician groups
  • Designed a Databricks observability app monitoring 140+ jobs, 19 apps, and 60+ materialized views, with warehouse usage alerts and runaway-job controls
  • Reviewed 63% of other contributors’ pull requests across four platform repositories; established pre-merge unit-test, lint, and Ruff formatting checks
Data Engineer at Medisolv
Jul 2023 - Jul 2025
  • Replaced monolithic notebooks with a Databricks Jobs/Workflows CLI ingesting 10B+ records weekly in parallel stages that support repair without a full restart
  • Led migration of 1,500+ Azure Data Factory pipelines to source control, adding local CLI editing and pytest checks for client-specific configuration
  • Automated client onboarding with Python and the Azure SDK, reducing over a day of manual setup to a five-minute deployment
  • Created and open sourced sparkparse, a Spark performance analysis tool that guided optimizations cutting task runtimes from hours to 10–20 minutes
Data Engineer (part-time contract) at UTHealth
May 2020 - Sep 2023
repo
  • Built the daily Texas COVID-19 data pipeline from state and third-party sources and became its sole maintainer
  • Collected source data with Python, REST APIs, BeautifulSoup, and Selenium, catching format changes with unit tests and a Slack monitoring bot
Data Analyst at NewYork-Presbyterian
Dec 2020 - Jul 2023
cost savings article
  • Replaced Excel-based CMS quality calculations with R pipelines processing 100M+ records weekly for 35,000 Medicare patients
  • Cut Tableau load times from 2–3 minutes to under 10 seconds with pre-aggregated tables and a star schema

Education

2018 - 2020
Master of Science in Epidemiology
UTHealth Houston
GPA: 3.8
  • Minored in biostatistics, with a thesis on biomarkers of traumatic brain injury (TBI)
  • Certificate in Data Science
  • Coursework included biostatistics, applied machine learning, and study design
2014 - 2018
Bachelor of Science in Public Health
University of Texas at Austin
GPA: 3.7

Studied public health, with coursework spanning biostatistics, infectious disease microbiology, and global health.

Extracurricular Activities

  • President of SURGe - a student-led organization connecting STEM faculty with students needing research experience

Projects

sparkparse
Spark metrics parser that exposes exploding joins and memory pressure to guide performance improvements
Python Spark OSS devtools
Panoctagon
Combat sports database and dashboard
Python Dagster dbt Plotly Dash DuckDB FastAPI CLI
jpmdb
Small data cleaning project to create a personalized movie database for my friend
Python Dagster dbt Plotly Dash DuckDB
Quinn
PySpark helper library downloaded 600k+ times per month
Python PySpark OSS devtools
TexasPandemics
Collection of epidemiology data powering the UTHealth COVID-19 dashboard
R Python Selenium REST Tableau