Zbigniew Mastylo, Developer in Austin, TX, United States
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Zbigniew Mastylo

Verified Expert  in Engineering

Software Developer

Austin, TX, United States
Toptal Member Since
December 7, 2022

Zbigniew is a pragmatic tech leader with 20 years of experience. He considers himself a polyglot, utilizing Python, Java, C#, C++, and C. He also understands architectural skills and scalability and has a working knowledge of Kubernetes, Google Cloud Platform (GCP), and AWS. Zbigniew enjoys working with clean and extensible code. He believes communication is essential. He treats technology as a tool to help solve business problems. Zbigniew can lead, mentor, code, and teach. He is flexible.


Python 3, RabbitMQ, Redis, Prometheus, Kubernetes, Google Cloud Platform (GCP)...
Blue Cross of North Carolina
Software Architecture, ArchiMate, Nuxeo, Salesforce Health Cloud, Genesys...
Aha!, Linux, InfluxDB, CI/CD Pipelines, PostgreSQL, Kubernetes, C#, Python...




Preferred Environment

Python 3, Google Cloud Platform (GCP), Amazon Web Services (AWS), Kubernetes, REST, FastAPI, MongoDB, PostgreSQL

The most amazing...

...real-time data pipeline I’ve implemented was for a company to scale quickly; Bivarus was eventually sold for 10 times its valuation.

Work Experience

Lead Software Engineer

2021 - 2022
  • Modernized the production codebase, reducing data pipeline crashes by 75% through reusable Python components in Python, Redis, RabbitMQ, and Prometheus.
  • Spearheaded common libraries in Python, increasing development speed by 40%.
  • Automated onboarding with bash scripts and makefiles, decreasing onboarding time by 60%.
Technologies: Python 3, RabbitMQ, Redis, Prometheus, Kubernetes, Google Cloud Platform (GCP), CI/CD Pipelines, Java, Linux, Docker

Senior Solutions Architect

2020 - 2021
Blue Cross of North Carolina
  • Led the architecture of a high-performance network (health insurance network). Helped to establish a national network with the product surpassing cost savings of 15%. Sold the product to employer groups representing over 30,000 members.
  • Led architecture and oversaw the delivery of an automation system for enterprise reporting saving $1.5 million in operating expenses.
  • Delivered provider data integration into Salesforce Health Cloud. Established the groundwork for critical initiatives.
Technologies: Software Architecture, ArchiMate, Nuxeo, Salesforce Health Cloud, Genesys, Amazon Web Services (AWS), Technical Leadership

Senior Technical Product Manager

2018 - 2020
  • Managed implementation and delivery of UI/UX MVPs. Improved compound curation time by 30% and compound search time by 500%.
  • Oversaw implementation and delivery of a data pipeline MVP. Replaced an unreliable monolith providing five times better scalability, data flow, and monitoring.
  • Implemented a POC in Python using InfluxDB. Collected lab machine data and established a foundation for further development.
Technologies: Aha!, Linux, InfluxDB, CI/CD Pipelines, PostgreSQL, Kubernetes, C#, Python, Technical Leadership

Chief/Software Architect

2015 - 2018
Multiple Startup Companies: Bivarus, Netsertive, Acupera
  • Delivered a greenfield data pipeline replacing unreliable systems using Python, Luigi, SQLAlchemy, and PostgreSQL. Provided means to scale MVP into a real-time and robust platform. Sold for ten times valuation to a market leader.
  • Implemented an ad lead delivery system (using Java, and Vertex). Established a foundation for real-time lead evaluation and processing.
  • Set up a clinical pathway test framework in C#. Allowed clinicians to test long-term care programs.
  • Trained engineers in applying solid principles and helped to improve overall code quality.
  • Coached and mentored engineers on solid principles. Set up hackathon sessions having engineers work on given use cases. Implemented clean and reusable solutions. Witnessed significant progress and code improvement from many engineers.
  • Conducted hundreds of code reviews providing comprehensive and meaningful feedback. Helped to improve overall code quality.
Technologies: Python 3, Java, C#, Flask, FastAPI, Vert.x, Luigi, PostgreSQL, MySQL, Docker, Amazon Web Services (AWS), Technical Leadership

Chief/Software Architect and Founder

2010 - 2015
Z-Evolution LLC
  • Led POC to establish a foundation for active transaction processing. Implemented a functional test suite in C++ on the HP NonStop SQL platform. Recommended DRNet for purchase.
  • Designed, implemented, and oversaw the delivery of a credit card refresh system in C++ on the HP NonStop SQL platform. Enabled active processing and increased throughput by 80%.
  • Designed and implemented in C++ reusable components wrapping hard-to-use HP NonStop SQL subsystem programmatic interface (SPI). Provided clean interfaces and reduced development time by 20-30%.
  • Implemented in C++ reusable pathway server wrapper libraries on the HP NonStop SQL platform. Reduced server development by about 30%.
  • Set up a fast data transfer service in C++ 11 on Linux. Used Boost.Asio library. Severed 1,000 clients pushing/pulling data from RAID devices on one Linux node. Surpassed SLA by 40 times.
  • Implemented transactional components in Java on HP NonStop SQL and OSS. Used for SWIFT initiatives accelerating development by about 30%.
  • Created a data collection service in Bash on Linux for TCP/IP, NSF, Samba, and storage systems. Enabled easy performance analysis, performance issue detection, and metric creation for the executive team.
Technologies: Java, C++, C, Boost, Boost.Asio, Linux, HP NonStop SQL, Technical Leadership

Senior Applications Engineer

2008 - 2009
  • Improved compliance system performance by about 40%. Used C++ on Unix. Provided faster trade execution.
  • Implemented dirty pricing for swaps in C++ on Unix for a hedge fund. Helped to expand the customer base and increase revenue.
  • Refactored a significant chunk of compliance-shared code in C/C++ on Unix. Made it solid, reusable, and testable. Accelerated feature development within the compliance system by 20-30%.
Technologies: C++, C, Unix, UNIX Utilities, Unix Shell Scripting, SQLite

Real-time Data Pipeline at a Healthcare Startup

The CTO hired me to help them scale and replace a poorly implemented, crash-prone Ruby-based system with a robust, fault-tolerant, and scalable data pipeline.
I didn't get many requirements, except that I entirely owned the product and made decisions on tech stack, design, and implementation. I took on the challenge, conducted quick research, and found an excellent Open-Source library, Luigi, from Spotify.
I read the docs, looked at APIs, and wrote a sample pipeline deciding the library would be a good run for us. I presented my findings to the team and instructed them to keep working on their current tasks while I set up the project.

I wrapped Luigi in simple code, hiding a few complexities of the framework while exposing base interfaces to implement new behavior. There was no need to know or understand what Luigi was.

The new pipeline implementation was relatively simple: figure out what tables to join to get data and how to process that data. On average, implementing a new data pipeline took three to eight days. I led and managed the project from inception to product delivery, helping Bivarus scale and acquire at ten times valuation. This was an excellent run for my team and me.

Restaurant Food Ordering Back End

I led the design and development efforts of the food ordering back end. The system was developed in Python using FastAPI, Postgres, Celery, and many Python libraries. It was fully integrated with Deliverect for real-time updates of restaurant menus.

Clinical Pathway Testing Framework

I designed and implemented an extensible pathway testing framework at healthcare startup Privis Health (former Acupera). The framework allowed nurses and medical staff to create and execute tests against long-term care plans created using Acupera Pathway Language.


Python 3, C++, Python, SQL, C#, Java, C




Software Architecture, Software Development, SOLID Principles, Architecture, Technical Leadership, FastAPI, APIs, Prometheus, CI/CD Pipelines, Salesforce Health Cloud, Genesys, Boost.Asio, UNIX Utilities, Unix Shell Scripting, Scrum Master, Team Leadership, Remote Team Leadership, Mathematics


Amazon Web Services (AWS), Linux, Docker, Google Cloud Platform (GCP), Kubernetes, Nuxeo, Unix, Azure


MongoDB, PostgreSQL, Redis, MySQL, HP NonStop SQL, SQLite, InfluxDB, Microsoft SQL Server


Flask, Vert.x, Boost


Luigi, SQLAlchemy


RabbitMQ, ArchiMate, Pytest, Aha!, Celery

1995 - 1999

Master's Degree in Computer Science

University of Missouri - Columbia, MO

1992 - 1994

Master's Degree in Mathematics

Adam Mickiewicz University - Poznan, Poland