Barbara Prusiewicz, Developer in Honolulu, HI, United States
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Barbara Prusiewicz

Verified Expert  in Engineering

Software Developer

Honolulu, HI, United States
Toptal Member Since
February 27, 2020

Barbara is a full-stack developer specializing in front-end development with expertise in React frameworks. Her passion is bringing user experiences to life. She was a software architect (C/C++) for point-of-sale terminals. Barbara designed and developed Verifone's Vx Contactless Card Payment app, which performs contactless card-based transactions used worldwide. This background provides her with a strong foundation in software engineering, development tools, and teamwork.


Vesta Housing Inc. DBA Aro Homes
React, UI Components, Amazon Web Services (AWS), Python, Bootstrap
Trailmapper, Inc.
React, TypeScript, JavaScript, CSS, GitHub, Waterfall Methodology, Recharts...
Citybase, Inc.
HTML, CSS, Headless Commerce, JavaScript, React, Front-end, GraphQL...




Preferred Environment

CSS, HTML5, AWS Amplify, JavaScript, React, Gatsby, jQuery, Mapbox SDK, Material UI, Tailwind CSS

The most amazing... I've developed is the contactless card payment app for Verifone point-of-sale devices. I smile whenever I tap a card to pay!

Work Experience

React Developer

2024 - PRESENT
Vesta Housing Inc. DBA Aro Homes
  • Implemented and delivered web app updates. The web app page includes a map view for identifying properties of interest, a Kanban page for managing property research tasks, and a Property Details page for property evaluation and comparison.
  • Collaborated with the client and primary users to identify requirements and UX flows.
  • Refined the client's UI design ideas as needed to ensure a consistent look and feel for the app.
Technologies: React, UI Components, Amazon Web Services (AWS), Python, Bootstrap

Senior Front-end Engineer

2023 - PRESENT
Trailmapper, Inc.
  • Developed a front-end MVP for fundraising CRM using React, TypeScript, Redux Toolkit with RTK Query, Recharts, and React Table.
  • Defined and refined user experiences. Client's UX included complex user stories for users to identify and manage collections of potential donors.
  • Designed the user interface (UI). Though the client had some initial Figma wireframes, they did not align with the user experience (UX) work. As needed, screen designs were adapted to meet the expected user requirements.
Technologies: React, TypeScript, JavaScript, CSS, GitHub, Waterfall Methodology, Recharts, Redux

Front-end Engineer

2022 - PRESENT
Citybase, Inc.
  • Fixed existing codebase for responsiveness of images and iframes. Prior to this work, pages with images or iframes often didn't render correctly on mobile causing usability issues.
  • Fixed multi-tiered navigation for accessibility. Prior to this work, it was not possible to navigate the Citybase websites using a keyboard.
  • Acted as a lead developer for a new category page populated from a GraphQL query and filterable based on properties of the content.
  • Served as a lead developer for improvements to the presentation of various blocks rendered from CMS content. Work required translating Figma mockups to React components using a proprietary design system.
Technologies: HTML, CSS, Headless Commerce, JavaScript, React, Front-end, GraphQL, React Redux, Software Development, Git, JavaScript 6, HTML5, Software Design

Senior Web Developer

2021 - PRESENT
  • Delivered mobile-first application (React) as a senior and primary front-end developer, allowing patients to track and check in for appointments.
  • Led test automation development for the patient-facing application using
  • Architected the front-end application to allow flexible support of different functionalities for A/B experiments.
Technologies: React, Material UI, Cypress, JavaScript, React Redux, Software Development, Git, JavaScript 6, HTML5, TypeScript

Lead Developer

2020 - PRESENT
Livable Hawaii Kai Hui
  • Designed webpages for a nonprofit group whose target audience is potential volunteers and partners.
  • Implemented the website using Webflow CMS to manage information on events and their locations.
  • Contributed to the website's ongoing effort, with more pages in the design and planning phases.
Technologies: Webflow, HTML, CSS

Lead Developer

2018 - PRESENT
No Problem Consulting
  • Collaborated on various pro-bono projects through as a lead developer and project manager. Projects range from a Chrome extension for reporting website projects to nonprofit websites (Gatsby, Webflow, and Mapbox SDK).
  • Provided MVP Dental Practice CMS allowing practices to pre-screen patients, communicate offers and options, and establish a relationship as a lead developer. Technologies used were React, AWS Amplify, and Figma.
  • Brought numerous releases for bio-pharmaceutical lab monitoring MVP as a senior developer. Responsibilities include front end (React and Redux) and administrative back end (Ruby on Rails).
Technologies: React, Gatsby, Redux, Material UI, Mapbox SDK, Webflow, AWS Amplify, Software Development, Git

Senior Front-end Engineer

2023 - 2024
Trailmapper, Inc.
  • Created MVP CRM for political fundraising using React with Redux (RTK and RTK Query). Styled the app with Material Tailwind and integrated functionality with Recharts and React Table Library.
  • Refined the UX based on evolving project goals. Improved conceptual wireframes and user flows initially defined by a UX designer to better align with Trailmapper's updated understanding of the problem.
  • Assisted with project management, defining tasks and dependencies, and scheduling corresponding work.
Technologies: React, TypeScript, JavaScript, CSS, GitHub, Waterfall Methodology

Front-end Developer

2023 - 2023
  • Updated the landing page to feature a video hero, a floating button for text sign-up, and other content changes. Also updated the site to improve the loading time, SEO scores, and accessibility (a11y).
  • Updated the website to improve loading time, SEO scores, and a11y.
  • Assisted the client with the Google tag setup, Google recaptcha setup, and Vercel deployments.
Technologies: React, Front-end, Next.js

React/UI Developer

2023 - 2023
  • Worked as the lead developer on a landing page refresh for a cryptocurrency exchange company.
  • Started with a base design from Figma wireframes and worked with the client to deliver an updated version of the website that more closely reflected Rubicon DeFi's culture and energy.
  • Contributed to the landing page, which is a Next.js site using Tailwind CSS for styling.
Technologies: JavaScript, React, Figma, HTML, CSS, User Interface (UI), UI Development, Tailwind CSS, TypeScript

React Developer

2022 - 2022
RNBW Holdings
  • Directed and executed website updates to reflect the change in the marketing strategy. Collaborated with the designer on styling details and content changes.
  • Addressed existing issues with mobile site styling.
  • Reviewed and corrected site deficiencies, including console warnings and package updates.
Technologies: Gatsby, React, HTML, JavaScript, GitHub, CSS, HTML5, Netlify, NPM, Figma, SCSS, Software Development

Lead Front-end React/JavaScript Developer

2021 - 2022
Volo Technologies LLC
  • Developed and delivered MVP application for analyzing credit card points. The application is responsive working on desktops, tablets, and phones. Technologies used: React, Redux-Saga, and MUI.
  • Developed test code for credit card analysis application using Jest.
  • Analyzed and debugged issues with WebSockets and back-end APIs.
Technologies: React, JavaScript, HTML, CSS, Material UI, Jest, Software Development, Git, JavaScript 6, HTML5

Senior Front-end Developer

2021 - 2021
  • Developed web components that processed various information from credit reports providing users with information such as debt analysis, credit report summaries, credit score simulation, and more. Component UI based on Figma designs.
  • Created developer documentation for web components so the components could be customized and embedded in web pages.
  • Investigated and analyzed bugs in the web components. Provided QA team with strategies for testing components and features, including error scenarios.
Technologies: JavaScript, CSS, HTML, Software Development, Git, JavaScript 6, HTML5, Software Design

Senior Front-end Developer

2020 - 2021
Rady Children's Hospital
  • Designed and developed a complex search form for the genomic research database application. Worked on the form that allows users to select from tens of thousands of possible values.
  • Developed the search results table functionality, which includes sorting, hiding, and sophisticated filtering functions to assist the user in navigating data for the same genomic research database application.
  • Managed software processes related to the delivery of the application, including issue tracking, release planning, and application bundling.
Technologies: JavaScript, jQuery, Bootstrap, Software Development, Git, JavaScript 6, HTML5

Principal Engineer

1990 - 2018
  • Managed complex investigations for customer software problems. Reduced incoming problem reports for new products by 25% by providing white papers, tutorials, and sample code for new features. Worked as the technical lead for the product support team.
  • Served as an architect and lead developer for the contactless card payment application. Designed a solution to meet industry requirements for performance, user interface, and card issuer certification. Managed an international development team.
  • Oversaw as the architect and developer a variety of projects ranging from operating system device drivers to network middleware to payment application frameworks. Contributed to all aspects of product delivery, training, and tier III support.
Technologies: C++, C, Software Development, Git, Software Design, Functional Programming

Dream Sports Africa
Gatsby app for non-profit fundraising. I was a senior developer on the pro bono team. Besides general development, my tasks included copy editing and Gatsby image optimization. The remote team is focused on helping non-profits use technology to meet their goals.

ToothFairy Lead Developer and Architect

Lead developer for an orthodontic/dental CRM allowing practices to track potential patients. I joined the project as the first developer taking over an initial proof-of-concept app. Working closely with a UI designer and domain expert, I designed and implemented features to bring the app to MVP and into MMP. I defined scalable processes for onboarding new clients and ensured HIPAA compliance.
Technology stack is React (with Material UI) using AWS Amplify, Cognito, and AppSync (DyanmoDB and GraphQL).

Landing Page Refresh
As the primary lead developer, I refreshed the Rubicon Finance landing page and general website.

The site uses Next.js with Tailwind CSS for styling. For the 3D animation, the Atropos package is used.

The changes were done from Figma wireframes and included all screen sizes. Web App provides a solution for bio-pharmaceutical labs to monitor equipment. Users can configure alerts and notifications, review incidents, and generate reports for FDA compliance. The web app consists of a React front end and a Ruby on Rails administrative back end. A separate Python back end handles the real-time monitoring of lab equipment.

As the lead developer for the web app, I was responsible for implementation and software design decisions related to the React and Rails components. Key aspects of the design and implementation include a RESTful API interface, AWS Simple Notification System (SNS) configuration for notifications (email and SMS), and a responsive user interface.

The project has progressed from the MVP stage to full customer evaluation.

ReadWriteCommunicate Literacy Analytics App
ReadWriteCommunicate is a literacy analytics application enabling stakeholders (students, parents, teachers, administrators) to monitor and analyze a student's literacy level. The literacy level is determined from writing samples using educational standards like the Flesch–Kincaid algorithm.

The ReadWriteCommunicate app consists of a React front end and Python Flask back end. As the primary front-end developer, I was responsible for the front-end design and implementation and defining the API interface with the back-end lead developer. The style for the front end is based on Material-UI. React-vis was used for data visualization (charts). The project was taken from a purely conceptual phase to MVP, which was distributed to a limited set of target users for evaluation. is a non-profit organization matching volunteers with immigrants needing assistance with tasks ranging from applying for citizenship to improving English skills.

As a volunteer software developer, I implemented new features and bug fixes for both the React front end and Rails back end. I am currently one of the senior developers responsible for reviewing Git pull requests and handling deployment to staging and production systems (AWS S3 and EC2 using Electronic Beanstalk).

News4u Sample Project

News4u provides users with access to news through different media outlets. It consists of a React front end with a Ruby on Rails administrative back end. The front end handles actual retrieval of news items. The Rails back end keeps track of user preferences like their favorite sources for news. This project was developed as part of the Flatiron full-stack developer bootcamp program. Aside from demonstrating concepts learned in the program, I also used React styled-components for presentation.

Source code available at

Verifone Vx Contactless Card Payment App

Verifone's Vx Contactless Card Payment app performs contactless card-based transaction (sales, refunds) processing. The app can run on any Verifone Vx product with contactless hardware. As with all payment applications, it requires certification for each type of payment card.
As the lead architect for the project, I was responsible for the overall application and design.

Key aspects of the architecture:
- Minimize re-certification requirements. The app is designed so specific handling requirements for each card type is in a separate contained module.
-Balance the PCI user interface requirements with the needs of specific clients to customize the user experience. This was accomplished by defining a small framework for the transaction user interface. For this project, I also implemented specific requirements of the architecture and managed the international development team.

Verifone Vx Products

The Vx product family spans multiple processor types (ARM9, ARM11), different hardware features (color screen, touch, portable battery), and different communications capabilities (dial, Ethernet, GPRS, WiFi).  A key goal for the product family was to allow the same application to run on multiple hardware variants.

As part of the Vx architecture team, I contributed to the delivery of the project at several levels:

-Operating System drivers: Developed console device driver and printer device driver.  
-Network Middleware: Designed system tasks used for managing network communications.  
-Extensive work helping new customer developers understand best practices, so their applications could run on multiple product variants. This included writing tutorials, sample applications, and white papers, as well as on-site mentoring and trouble-shooting. 

Livable Hawaii Kai Hui
Designed and delivered (implemented in Webflow with a custom JavaScript and Mapbox SDK) a website for a land stewardship nonprofit. For the organization, it was essential to capture both their work on the land and respect for the native Hawaiian community.
1977 - 1980

Bachelor of Science Degree in Computer Science

Syracuse University - Syracuse, New York, USA


Introduction to Web Accessibility



Full-stack Developer Bootcamp

Flatiron School


Database Management Essentials (SQL)



User Interface Prototyping and Design



User Interface Research and Design



Introduction to User Interface Design



React Redux, React, AWS Amplify, REST APIs, jQuery, Recharts


Git, Amazon Cognito, AWS AppSync, Amazon Simple Notification Service (Amazon SNS), GitHub, NPM, Figma


Redux, Ruby on Rails 5, Ruby on Rails (RoR), Material UI, Bootstrap, React Native, Cypress, Jest, Next.js, Tailwind CSS, Ruby on Rails 4


JavaScript, HTML, JavaScript 6, HTML5, CSS, C, C++, SCSS, TypeScript, Ruby, GraphQL, SQL, Python


Amazon DynamoDB, Amazon S3 (AWS S3)


Functional Programming, RESTful Development


AWS Lambda, Amazon EC2, Amazon Web Services (AWS), Webflow, Netlify


Software Design, Software Development, Front-end, A11Y, Gatsby, Web Accessibility, Mapbox SDK, Headless Commerce, User Interface (UI), UI Development, Waterfall Methodology, UI Components, i18n

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