Roxana Chiorean, Developer in Truckee, CA, United States
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Roxana Chiorean

Verified Expert  in Engineering

Software Developer

Truckee, CA, United States
Toptal Member Since
June 6, 2019

Roxana is a senior back-end engineer with nearly a decade of professional experience in both large corporations and startups. After being an open source contributor for the OpenStack cloud framework while at Hewlett Packard Enterprise, she joined a healthcare startup where she specialized in big data processing technologies. Roxana is a friendly individual with a passion for building great multicultural teams.



Preferred Environment

MacOS, Ubuntu, Vim Text Editor, PyCharm, Git

The most amazing...

...project I've worked on was a data quality visualization dashboard to help users better understand and monitor the quality of data over time.

Work Experience

Senior Software Engineer

2016 - 2019
Nuna Health
  • Worked on different components of the ETL data processing pipeline and Spark cluster configuration.
  • Helped build data-quality tools to analyze the quality of the processed data.
  • Designed and built a data quality visualization dashboard.
  • Scaled the data platform to be able to process hundreds of terabytes of data.
  • Helped build an API to match patients to primary care providers using Python and Django.
  • Designed and built a web page and a notification system around SLAs for client data.
  • Worked with data scientists to scale the data modeling algorithms.
Technologies: Amazon Web Services (AWS), Apache Airflow, Looker, Spark, Scala, Java, Django, Python

Software Developer

2015 - 2016
Hewlett-Packard Enterprise (HPE Helion Cloud)
  • Contributed to the open source cloud framework project OpenStack, specifically to the authentication and authorization service.
  • Became involved in the open source community by doing code reviews for the other members in the community and participating in planning meetings.
  • Implemented a web single sign-on authentication for HPE Helion Cloud.
  • Improved the OpenStack client command line interface (CLI).
  • Improved the authentication mechanism using LDAP driver integration.
  • Contributed to the open source Python library, ldap3, with code that enabled unit test mocking capability.
Technologies: Ansible, OpenStack, Python

Software Developer | Team Lead

2011 - 2015
Hewlett-Packard Enterprise (HP Database and Middleware Automation)
  • Established workflows which automated database and middleware administration tasks.
  • Implemented internationalization and localization of the code.
  • Acted as a system architect and team lead and mentored interns and more junior engineers.
  • Improved code quality by standardizing the code review process.
  • Led projects involving integrations with other HPE software products.
Technologies: Java, Python

Malware Researcher

2010 - 2011
  • Analyzed the behavior of new malware through reverse engineering.
  • Added detection for the new viruses into the antivirus product.
  • Developed anti-malware heuristic techniques.
  • Created an algorithm to detect illegal key generators through dynamic behavior analysis and image processing.
  • Developed an algorithm to avoid false positive alerts.
Technologies: Reverse Engineering, Assembly, Python, C

Data Quality Visualization Dashboard

At Nuna Health, as part of the data processing pipeline, we generated a lot of data quality metrics and validations. The problem was that there were so many metrics and validations that it got out of control for a human to comprehend all those generated numbers anymore, so this situation created a lot of manual work.

I started designing a data quality visualization dashboard that would make it easier for users to understand better and monitor the quality of the data.

The design process involved user interviews to better understand the project requirements, a couple of brainstorming sessions and multiple prototypes.

I chose to implement the dashboard using Looker, a business intelligence tool that has nice visualization capabilities for big data analysis. Using Looker's own data modeling language (LookML) I implemented a set of dashboards around the overall quality of the data of a client run, comparison between multiple data processing runs and graphs that highlighted spikes in changes of the data quality over time.

This tool was used by data operator users and eliminated tens of hours of manual work per month.

Primary Care Provider Matching API

When I worked at a healthcare startup, I helped design and develop a RESTful API for matching a patient with the best available doctor given a set of constraints like health condition, physical location, age, and more.

It was a very impactful project, shipped to health insurance providers to improve the outcome of patients health care.

Technologies: Python, Django

Data Calendar Web Page and Notification System

During my time at Nuna Health, I designed and implemented a system for client data schedule management and notifications around important data events.

This system kept track of the expected schedule for receiving client data, late data updates, expected SLA deliverable dates. I built a web page to display all this information in a user-friendly visual way and a notification system which alerted users via email for important events like late data, the moment when all of the monthly data for a specific client has arrived, and so on.

This project was developed using Python/Django and Angular and helped reduce a lot of manual work by data operator users who were keeping track of all this information manually in an Excel spreadsheet. It also helped avoiding missing important deadlines.

Open Source Contributions for Openstack

For one and a half years, I had the unique opportunity to be one of the HPE's contributors to the open source project OpenStack. I contributed to multiple parts of the OpenStack repository, and it gave me the opportunity to interact with highly talented developers from other companies which were contributing to OpenStack (IBM, Red Hat, Rackspace, and more).
2010 - 2012

Master's Degree in Distributed Systems

Babeș-Bolyai University - Cluj-Napoca, Romania

2007 - 2010

Bachelor's Degree in Computer Science

Babeș-Bolyai University - Cluj-Napoca, Romania


Scrum Master

Agile Development School




Git, Spark SQL, AWS CloudFormation, Jenkins, Amazon Elastic MapReduce (EMR), PyCharm, Vim Text Editor, Apache Airflow, Looker, Ansible


Django, Spark


Agile Software Development, RESTful Development, Functional Programming


Python, SQL, Java, C, Assembly, Scala


Amazon EC2, Linux, Databricks, OpenStack, Ubuntu, MacOS, Amazon Web Services (AWS)


Amazon S3 (AWS S3), MySQL, MongoDB


Data Engineering, Reverse Engineering

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