Patrick F. Callahan

Data Developer | Team Lead

Bringing AI, business logic, Cloud Infrastructure, and clients together to create data solutions that actually work.

Patrick F. Callahan

About Me

I'm a Data Developer with a decade of experience in designing, building, and maintaining data infrastructure that serves businesses with clear insights that matter.

I have extensive experience on all sides of the modern data stack:

  • Getting data where it lives in the wild
  • Constructing Cloud Databases to hold that data
  • Ingesting and transforming it via scheduled, event-driven, or real-time streaming pipelines
  • Serving it to the client, be that a dashboard, an application, a Data Analyst, or a Data Scientist

I specialize in the Financial Services and Insurance sector, and in the Snowflake Data Ecosystem ❄️

Technical Skills

Languages

Python SQL JavaScript

Data Platforms

Snowflake Snowpark Databricks

Tools & Frameworks

dbt Fivetran Coalesce Airbyte

Cloud & DevOps

AWS (S3, Lambda, IAM) Git GitHub Actions

Data Architecture

RBAC Kimball Modeling Medallion Architecture

Leadership & Tools

AI-Driven Development (Claude, MCP) Project Leadership Client Relationship Building Asana Jira

Certifications

Snowpro Advanced Data Engineer Certification

Expires Feb 2027

View Credential

Projects

Professional Experience

Lead Consultant

Atrium AI - Bozeman, Montana (Remote)

June 2025 - Present

DE Lead - Asset Management Firm

Nov 2025 - Present

Led Architecture and Engineering efforts for an Asset Management firm optimizing their existing Snowflake implementation.

  • Worked on a pilot project to simplify spaghetti code and optimize existing pipelines by migrating from Procedures to dbt
  • Implemented DevOps, Disaster Recovery, Comprehensive Data Masking, and Sandbox, Dev, QA, Preprod, and Production Environments
  • Refactored legacy reporting, reducing compute from ~110 minutes per refresh to 5-8 minutes per refresh
  • Laid a data model foundation using Medallion and Kimball architectures to allow the firm to expand their optimization efforts

DE Lead - Large Fortune 500 Tech Corporation

June 2025 - Nov 2025

Led Architecture and Engineering efforts for a large tech corporation building a Snowflake pipeline to power their end-user applications.

  • Worked with the Client to build an end-to-end POC design
  • Implemented design across rapid sprints, working with multiple other engineers on the Client and Atrium side
  • Wrote and executed multithreaded scripts to produce billions of rows of fake data for testing purposes
  • Conducted benchmark testing to prove out the robustness of the pipeline implementation

DE Lead - Small Tech Firm

June 2025 - Oct 2025

Led Architecture and engineering efforts in an ARR Dashboard project. The goal was to bring this team out of Excel and into the modern cloud data space.

  • Led the database design and modeling, including end-to-end RBAC and Kimball-type Entity Relationships
  • Built pipelines to continuously ingest from S3 buckets to Snowflake for multiple data sources
  • Working with another engineer, built a DAG in dbt for end-to-end transformations that harmonized ARR data from many sources
  • Worked with Client and Atrium-side Analysts to construct SQL Reports based off of dbt output models

Sr Consultant I, Data Engineering

Hakkōda, an IBM Company - Heredia, Costa Rica (Remote)

July 2023 - June 2025

Senior Engineer - Large Agrochemical Corporation

Feb 2025 - June 2025

Worked with a small team to build a Genetic Relational Data Graph (Pangenome) to help predict all possible haplotypes across the genomes of key species of interest.

  • Built custom parsers (Snowpark, Python) for massive genetic line files
  • Restructured data to fit a Graph AI tool being tested as part of a POC (RelationalAI)
  • Benchmarked RelationalAI performance against Client's existing inference methods

Lead Engineer - Asset Management Firm

Mar 2024 - Feb 2025

Led Engineering efforts in a data migration project. Data was moved from On-Premise legacy systems into Snowflake. The goal was to provide their Back-Office departments with improved Data Quality and faster return times on reporting for tasks like NAV Reconciliation, Position Reconciliation, and Management Fee Analysis.

  • Led team efforts in building and maintaining a production data pipeline, transforming raw data through staging, modeled, and reporting layers using Kimball Methodology (Fact Tables, SCD I/II, etc.)
  • Data was ingested from on-premise SQL Server instances via Fivetran. Transformations and unit testing was implemented in Coalesce, with a DAG of about 400 Nodes. Version Control & CI/CD handled with Azure DevOps
  • Simultaneously owned production support and development of new features from sprint to sprint
  • Onboarded new developers to the project, upskilling them by providing documentation and 1-1 time to help newcomers understand the project's tech stack and work policies

Lead Engineer - Private Software Corporation

Sep 2023 - Feb 2024

Led Engineering efforts in a project to refactor and repurpose large amounts of legacy logic. The goal was to improve accuracy and efficiency of existing reporting on Customer Accounts and expose/correct inconsistencies in how business rules had been understood and applied.

  • Oracle Data was migrated into Snowflake using Airbyte for ingestion, dbt for Data Transformation & Validation, and Azure DevOps for Version Control & CI/CD
  • Refactored thousands of lines of SQL from stored procedures and existing Oracle models, breaking them into reusable components such as dimension tables, parameterized views, or mapping tables
  • Brought runtime for report generation down from approximately 3.5 hours to 8 minutes
  • Worked with business analysts and junior Developers to produce an interactive PowerBI Dashboard for C-Suite Employees

Analytics Engineer

CMS Payments Intelligence, Inc - Atlanta, GA

Jan 2022 - May 2023

Worked on a team of Developers to serve data pipelines, SQL Reporting, client dashboards, and other data products to Consulting Teams working with Large vendor clients. This enabled clients' massive streams of customer payment data from processors such as Adyen, Chase, Fiserv, Braintree, Elavon, etc. to be easily summarized, filtered, and drilled into to gain financial insights.

  • Worked under a product owner for specific client-based engagements
  • Used Databricks for all Cloud Data Processing, heavily leveraging both Databricks SQL and the PySpark API as needed
  • Processed data using a medallion architecture, organizing Gold-layer objects into a business-defined logical hierarchy
  • For data ingestion, leveraged a wide variety of Python-based techniques: webscraping, PDF parsing, API calls, FTP, etc.
  • Built interactive PowerBI Dashboards to satisfy client requirements, working iteratively with internal consulting team

Data Analyst

LabArchives, LLC - San Diego, CA (Remote)

Feb 2017 - Dec 2021

Functioned as the go-to Data person at a small WebApp company. Developed and supported a catalog of SQL Reports, PowerBI Dashboards, and other Data Assets to satisfy the needs of various company Departments.

  • Maintained a deep understanding of the WebApp's Data Structure in MySQL, including all data definitions and business rules
  • Leveraged Python to send reports out via email on a scheduled basis
  • Used PowerBI to develop a catalog of Dashboards to allow users to quickly search and filter for the data they need
  • Developed SQL Reports from scratch; debugged and optimized existing reporting as data grew and changed

Product Specialist / Customer Support Representative

LabArchives, LLC - Remote

Jun 2014 - Nov 2020

Maintained high level of product knowledge and trained coworkers and customers on product features via online and in-person meetings. Received and handled Support tickets via phone call and email quickly, effectively, and professionally.

  • Constructed presentation materials to lead customer webinars
  • Held both strategic in-person Presentations and regular online webinars to get customer interest and answer questions
  • Used Kayako for IT Support Desk work (Emails/Tickets, Phone Call support, etc)
  • Worked with Development Team to QA new features; communicated customer feature requests to Development
  • Maintained relationships with the Administrators of key Enterprise accounts

Education

Master's in Information Technology

George Mason University - Fairfax, VA

Aug 2018 - May 2021

Bachelor's in Chemistry

George Mason University - Fairfax, VA

Aug 2010 - May 2014

Get In Touch

I'm always interested in discussing data engineering challenges, new opportunities, or just connecting with fellow data professionals.