Sean is available for hire
Hire SeanSean Shaifubahrim
Verified Expert in Engineering
Full-stack Web Developer
Vancouver, BC, Canada
Toptal member since May 23, 2022
Bio
Sean is a full-stack developer specializing in React, React Native, and web accessibility requirements. With five years of professional experience, he became an expert in developing end-to-end web and mobile apps, excelling in WCAG Level AA-compliant web solutions. Sean is always committed to producing quality code that helps scale businesses.
Portfolio
Amazon
React, Java, TypeScript, AWS IoT, HTML, CSS, Sass
Modivcare
React, React Native, Java, Git, TypeScript, JavaScript, Mobile Development...
Tension Climbing
React Native, Firebase, Mobile Development, Redux, Front-end Development...
Experience
- Front-end Development - 5 years
- JavaScript - 5 years
- Git - 5 years
- React - 4 years
- WCAG 2 - 4 years
- TypeScript - 4 years
- React Native - 4 years
- Firebase - 3 years
Availability
Part-time
Preferred Environment
Slack, Confluence, GitLab, GitHub
The most amazing...
...accomplishment I've achieved is taking part in the restricted worldwide group of almost 950 certified IAAP web accessibility specialists (WAS).
Work Experience
Front-end Engineer 2
2023 - PRESENT
Amazon
- Developed and maintained Amazon's Global Online Brand Store platform using modern front-end and back-end technologies, including React, HTML, CSS, JavaScript, and Java.
- Collaborated with cross-functional teams, including Amazon Store's product management teams, UI/UX designers, customer support teams, and back-end developers, to design and implement scalable and maintainable front-end architectures.
- Ensured the quality of front-end code by establishing and enforcing coding standards, conducting code reviews, and implementing automated testing strategies (unit, integration, and end-to-end testing) to maintain a robust and reliable codebase.
- Identified and resolved performance bottlenecks in front-end code using techniques like code splitting, lazy loading, and image optimization to enhance load times and reduce resource usage. This includes monitoring and improving website performance.
- Designed, developed, and implemented A/B tests within the front end of web applications. This includes creating variations of user interfaces, integrating experimentation frameworks, and ensuring accurate data tracking and reporting.
Technologies: React, Java, TypeScript, AWS IoT, HTML, CSS, Sass
Full-stack Developer
2021 - 2022
Modivcare
- Oversaw the development of Modivcare's care manager dashboard. It is a React application and works as the company's internal portal for healthcare providers to administer care to health insurance beneficiaries.
- Took part in the team that developed and maintained Modivcare's main React Native application used by patients and caregivers to schedule non-emergency medical transportation (NEMT).
- Acted as the subject matter expert on web accessibility. Programed accessible applications, advised engineers and designers on Web Content Accessibility Guidelines (WCAG), and explained the Americans with Disabilities Act (ADA) requirements.
- Incepted Modivcare's React Native component library to house components shared by all Modivcare's React Native applications, ensuring a consistent branding that is easily maintained.
- Mentored multiple junior software developers from the Denver and India offices, reviewing their code and guiding them on best practices and implementations.
Technologies: React, React Native, Java, Git, TypeScript, JavaScript, Mobile Development, HTML, CSS, CSS4, HTML5, Redux, SQL, Front-end Development, Front-end, Web Components, Mobile, Mobile App Development, Web App UI, WebApp, iOS, Figma, REST APIs, Amazon Web Services (AWS), Microservices, Full-stack, APIs, User Experience (UX), Mobile Apps
Full-stack Developer
2020 - 2022
Tension Climbing
- Adopted and overtook Tension Climbing's main mobile application development and maintenance, acting as a lead developer in charge of all code decisions and implementations.
- Administered alpha, beta, and production releases and managed the application's App Store Connect and Play Store Console accounts.
- Implemented screens and algorithms, which employed a machine learning API that calculated sports performance and included React Native data visualization.
Technologies: React Native, Firebase, Mobile Development, Redux, Front-end Development, Front-end, Web Components, Mobile, Mobile App Development, Expo, Web App UI, WebApp, iOS, Full-stack, APIs, User Experience (UX), REST APIs, Mobile Apps
Full-stack Developer
2021 - 2021
Chop Dawg
- Architected and developed web and mobile solutions for clients. Depending on their project size, wants, and needs, I would design React, React Native, AWS, and/or Google Cloud solutions and then implement them.
- Led development teams of 1-5. Besides regular full-stack development, I would also conduct code reviews and mentor junior developers as a lead developer.
- Developed a business-social mobile application that shared electronic business cards. Besides a React Native application, a Content Management System (CMS) portal was also developed in React. All back-end infrastructures were housed in AWS.
- Developed an application that lets users schedule regular donations to nonprofit organizations. Stripe API was heavily utilized to manage transactions and automate the onboarding of nonprofit organizations.
Technologies: React, React Native, Firebase, Mobile Development, HTML, CSS, Node.js, MongoDB, CSS4, HTML5, Redux, SQL, Stripe, Front-end Development, Front-end, Web Components, Google API, Mobile, Mobile App Development, Expo, React Native for Web, Monorepos, Web App UI, WebApp, iOS, Figma, AWS Lambda, REST APIs, Amazon Web Services (AWS), Full-stack, APIs, User Experience (UX), Mobile Apps
Full-stack Developer
2019 - 2021
7D Imaging
- Developed a React Native tablet application designed to be an educational tool for medical students learning ultrasound techniques. The app had a heavy dependency on React-Native-video, React-Native-SVG, and React-Native-pdf.
- Developed an authoring tool in React to create time-series data that would supplement ultrasound videos. The app would use this data to overlay SVG points or polygons on top of ultrasound videos and images.
- Architected the AWS infrastructure that both applications would use. The AWS Amplify suite was mainly used.
Technologies: React Native, AWS Amplify, TypeScript, JavaScript, HTML, CSS, React, Data Structures, Front-end Development, Front-end, Web Components, Mobile, Mobile App Development, Web App UI, WebApp, iOS, PHP, AWS Lambda, REST APIs, Amazon Web Services (AWS), Full-stack, APIs, User Experience (UX), Mobile Apps
Experience
Modivcare Care Manager Dashboard
A React application that serves as Modivcare's internal web portal for healthcare providers to administer care to insurance beneficiaries. Due to the prevalence of electronically protected health information (ePHI) in this application, compliance with Health Insurance Portability and Accountability Act (HIPAA) was necessary, and strict security measures were enforced.
Modivcare Member App
Modivcare's main mobile application for healthcare recipients. The main functionality is for users to schedule non-emergency medical transportation. e.g., trips to the dialysis appointments covered by their health insurance.
I was one of the full-stack engineers in a team of six that continuously developed and maintained the software. Since ePHI was prevalent, security was a heavy priority to abide by HIPAA regulations.
I was one of the full-stack engineers in a team of six that continuously developed and maintained the software. Since ePHI was prevalent, security was a heavy priority to abide by HIPAA regulations.
Don't Go Travel Survey App
https://survey.dontgo.travel/A Next.js survey application for determining a user's travel persona. This app would calculate results based on a weighted formula and then collect these results for business use.
Single Sign-On authentication was required and was done so via Auth0. I also developed a dynamic approach to manipulating page meta-data for sharing content-specific Facebook posts.
Single Sign-On authentication was required and was done so via Auth0. I also developed a dynamic approach to manipulating page meta-data for sharing content-specific Facebook posts.
Education
2015 - 2019
Bachelor of Science Degree in Computer Science
University of Colorado Boulder - Boulder, Colorado, USA
Certifications
MAY 2022 - MAY 2025
Web Accessibility Specialist
International Association of Accessibility Professionals
Skills
Libraries/APIs
React, Node.js, React Native for Web, REST APIs, Stripe, Google API, Google Maps API, AWS Amplify, Facebook SDK
Tools
Git, Expo, Figma, Slack, Jira, Confluence, Auth0
Languages
JavaScript, TypeScript, HTML, CSS, CSS4, HTML5, SQL, C++, Python, Java, PHP, Sass
Frameworks
React Native, WebApp, Next.js, Redux, Spring, Material UI
Paradigms
Mobile Development, REST, Microservices
Platforms
Firebase, Mobile, iOS, AWS Lambda, Amazon Web Services (AWS), AWS IoT
Storage
MongoDB, Google Cloud, PostgreSQL
Other
WCAG 2, User Experience (UX), Front-end Development, Front-end, Web Components, Web App UI, Mobile Apps, Web Development, Mobile App Development, Monorepos, Full-stack, APIs, Algorithms, Data Structures, User Interface (UI)
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