Mary I Sheahen, Developer in Narragansett, RI, United States
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Mary I Sheahen

Verified Expert  in Engineering

Software Developer

Narragansett, RI, United States
Toptal Member Since
February 5, 2019

Mary is an experienced web developer with a passion for user experience and 9+ years of industry expertise. With a master's degree in computer science and extensive experience freelancing for front-end projects, Mary is well-positioned to tackle any project.


Amazon Web Services (AWS), Java, Swift, HTML, JavaScript, MySQL, PHP, CSS3
Data Provenance Admin UI
React, OpenShift
Thru The Bible
Amazon Web Services (AWS), TypeScript, React, React Native, Spring Boot




Preferred Environment

CSS, HTML, JavaScript, React

The most amazing...

...aspect of UX is creating applications that are not only beautiful but work for your target user.

Work Experience

UX Development Lead

2018 - PRESENT
  • Implemented architecture for a hybrid mobile app by creating SQLite database handlers, controller, and views.
  • Created Android and iOS custom functions to access phone-specific controls such as camera access, speech recognition, and gallery photo pickers.
  • Contributed to and helped maintain PHP API endpoints, ensuring tight security and fast performance.
  • Created pixel perfect implementations of custom designs provided by the design team, ensuring responsiveness overall device sizes.
  • Created a lightweight custom javascript framework to handle data passing from native mobile features to unified JavaScript UI.
  • Implemented CSS animations for over 4 games. Animation styles included a countdown ticker loading layer, moving backgrounds on the games, and success/failure animations on certain game actions.
Technologies: Amazon Web Services (AWS), Java, Swift, HTML, JavaScript, MySQL, PHP, CSS3

Front-end Engineer

2021 - 2022
Data Provenance Admin UI
  • Worked for a client (a government agency) that created a data provenance system, which allowed monitoring and inspecting workflows and changes to data products.
  • Created a front-end application that worked as a test harness to upload, test, and inspect pieces of data and edit workflows.
  • Built the front-end application, which leveraged and React and connected to a Java Spring Boot back end.
Technologies: React, OpenShift

Mobile and Full-stack Engineer

2021 - 2022
Thru The Bible
  • Created, tested, and deployed back-end APIs (Java Spring Boot) for the bible application. It was launched into production in late 2021.
  • Built an audio tracking system and integrated back-end endpoints with the front-end React Native application.
  • Wrote automated tests and integrated them with the CI deploy pipeline for more content deployments.
Technologies: Amazon Web Services (AWS), TypeScript, React, React Native, Spring Boot

UI Developer

2019 - 2022
Metriva Technologies
  • Created from scratch and successfully launched an Angular-based UI healthcare platform.
  • Integrated a third-party OAuth system for user session logins.
  • Planned and implemented re-useable components in the system with custom styling and functionality.
Technologies: HTML, CSS, Sass, User Interface (UI), User Experience (UX), Angular, RxJS, Material Design, Theme Development, Pixel Perfect

Front-end Developer | iOS Developer

2019 - 2020
GSK (Freelance Contract)
  • Used React to build web portal for viewing, managing and submitting sensitive user data.
  • Implemented logic for authenticating users via Implicit Grant and then later through Authorization Code Grant types.
  • Used Google's Speech-to-text API and grpc streaming with iOS app to record voice recordings and convert to text transcript.
Technologies: Auth0, Node.js, Google Cloud Platform (GCP), Swift, React

Front-end Engineer

2019 - 2020
Quartz Network (Freelance Contract)
  • Implemented React responsive web application for the social network of professionals including features like connections, messaging, and admin functions.
  • Constructed embedded posts for social media entries using complex regex logic, displaying HTML content based on user-input data.
  • Implemented rich text editor for user content using Draft.js.
Technologies: Loopback, React

Front-end Engineer

2019 - 2019
JoyBird (via TopTal)
  • Polished complex React components and created CSS animations for an eCommerce site.
  • Implemented React components to display dynamic menu items.
Technologies: Storyboarding, GraphQL, React

Front-end Developer

2019 - 2019 (via TopTal)
  • Implemented and collaborated on new designs for context menus and tooltip menus for canvas-based drawing tool.
  • Created new components in React that allowed for text manipulation.
  • Leveraged Fabric.js methods in order to update font styles and integrated into text changing components.
Technologies: Fabric, JavaScript, HTML, CSS, Canvas, React

UX Developer

2015 - 2018
Fidelity Investments
  • Worked closely with a team of designers and developers to implement working prototypes for web-based financial applications.
  • Successfully delivered over 12 projects over the three year period.
  • Contributed and maintained custom Angular2 based UI framework used across multiple applications in the organization.
Technologies: SQL, JavaScript, HTML, CSS, Ember.js, SCSS, Angular

Full-stack Developer

2014 - 2015
  • Implemented web and mobile applications for a mobile web-based social media application.
Technologies: CSS, SCSS, JavaScript, HTML, MySQL, PHP

Data Visualization Project

This project used Highcharts.js and d3.js to help visualize data that was being collected about nursing home residents and their health activity. I re-designed and developed a new web interface using responsive design techniques. The web interface was then used for viewing clinical data stored in a MYSQL database, involving writing complex queries and using PHP, CSS, HTML, JavaScript, and jQuery.


HTML, JavaScript, CSS3, CSS, Swift, PHP, Java, SCSS, SQL, GraphQL, Sass, TypeScript


Angular, Ember.js, React Native, Loopback, Spring Boot


React, Highcharts, D3.js, Fabric, Node.js, RxJS




CSS3 Animation, Storyboarding, User Interface (UI), User Experience (UX), Material Design, Theme Development, Pixel Perfect


Android, iOS, Google Cloud Platform (GCP), Amazon Web Services (AWS), OpenShift


Canvas, Auth0

2011 - 2015

Master's Degree in Computer Science

University of Missouri - Columbia - Columbia, MO

2007 - 2011

Bachelor's Degree in Biological Engineering

University of Missouri - Columbia - Columbia, MO


Senior Web Developer Nanodegree


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