Samuel William Salefske
Lead Data Engineer
Profile
Lead Data Engineer with 10+ years of experience architecting cloud-native data platforms for high-volume transaction processing. Currently own 100+ production pipelines (built roughly 50, maintain roughly double that) processing volumes from 50,000 to millions of transactions daily on AWS and Snowflake. Led a cost-reduction initiative migrating pipelines from AWS Glue to Lambda, cutting compute costs across the platform. Serve on an architecture review board, mentor junior engineers, and translate ambiguous business requirements into governed, scalable data solutions. AWS Certified Cloud Practitioner.
Experience
Continuous role through Mastercard's acquisition of SessionM and its later divestiture to Capillary Technologies
Lead Data Engineer
Mar 2026 – Present
- Own and architect 100+ data pipelines (built ~50 from scratch, maintain ~100 total) processing transaction volumes ranging from 50,000 to several million records daily, supporting star-schema reporting layers and normalized operational stores.
- Led a platform-wide migration of pipelines from AWS Glue to AWS Lambda, reducing compute costs while maintaining throughput and reliability on high-volume transaction processing domains.
- Serve on the architecture review board, evaluating new technical solutions and setting platform standards for data modeling and governance.
- Lead client workshops and design sessions to produce Business Requirements Docs and Testing Plans/Frameworks for cross-functional engineering initiatives.
- Mentor 2 junior engineers through weekly 1:1s; run onboarding lunch-and-learns for new hires.
Senior Data Engineer
Sept 2023 – Mar 2026
- Guided engineering teams on secure coding standards and vulnerability remediation strategy.
- Designed, architected, and maintained API-based integrations across internal and external systems using Python, SQL, and Java.
Data Engineer
Aug 2021 – Sept 2023
- Built and maintained API-based integrations across internal and external systems using Python, SQL, and Java.
- Implemented cloud-native solutions in AWS to improve scalability and reliability of data platforms.
Senior Consultant
Oct 2019 – Aug 2021
- Designed and implemented an enterprise Third-Party Risk Management system covering hundreds of vendors across roughly 59 business units.
- Built executive-level dashboards aggregating enterprise-wide risk metrics for leadership visibility.
- Developed governance frameworks across multiple domains to reduce development and production issues.
- Led client workshops, requirements-gathering sessions, and end-user training.
Information Security Specialist
Mar 2019 – Oct 2019
Application Developer
Feb 2018 – Mar 2019
- Rebuilt an enterprise Risk Management module integrating the internal software catalog and evidence repositories.
- Built Windows listener services integrating APIs with internal systems for automated risk rating.
- Led system upgrades and platform scaling initiatives.
Developer
Sept 2015 – Feb 2018
Associate Developer
May 2014 – Sept 2015
- Developed custom C#/.NET integrations between Archer and external systems and designed event-driven, automated data feed workflows.
- Led technical sales discussions and requirements-gathering sessions.
Technical Skills
Languages
Python, SQL, Java, C#, REST APIs, XML, JSON
Data Modeling & Governance
ER Modeling, 3NF, Normalized & Denormalized Design, Star/Snowflake Schemas
Cloud Platforms & Storage
AWS (S3, Glue, Lambda, Redshift), AWS Glue Data Catalog, Snowflake, Databricks / Delta Lake
Data Integration & Quality
ETL/ELT Pipeline Design, Batch & Streaming Pipelines, Data Quality Frameworks, Cross-System API Integration
DevSecOps & Tooling
CI/CD (Jenkins / GitHub Actions), Git, JIRA, Splunk
Education
Bachelor of Science — Security & Information Assurance (Biometric Security)
Davenport University
Associate of Applied Science — Security & Information Assurance
Davenport University
AWS Certified Cloud Practitioner