Joel Frank, Mobile Application Developer in São Tomé de Covelas, Portugal
Joel Frank

Mobile Application Developer in São Tomé de Covelas, Portugal

Member since December 19, 2019
With a Ph.D. in computer science and over 18 years of experience creating mobile applications, Joel has a passion for creating flawless user interfaces and applications that exceed expectations. In addition, his knowledge of databases and back-end requirements gives him a deep understanding of an application's complete architecture.
Joel is now available for hire




São Tomé de Covelas, Portugal



Preferred Environment

Unix, Android, iOS

The most amazing...

...project was leading a diverse, distributed team to not only meet all strategic goals for the year but did so while maintaining a 47% retention rate for the app.


  • Head of Engineering | Senior iOS Engineer

    2018 - 2019
    • Managed a small-but-highly-effective engineering team that was able to change how a Fortune 50 company creates and maintains its software.
    • Created the core fleet application that became the Cat app: Caterpillar's central flagship mobile application.
    • Effectively mentored several team members from being on the verge of termination to being senior, reliable, engineers who now help to drive the team's vision and mentor others.
    • Oversaw the transformation of the team's strategic roadmap into actionable sprint plans while meeting the ever-changing requirements of the company's product owners and stakeholders.
    Technologies: Agile, Firebase, Xcode, iOS SDK, OAuth, REST, PostgreSQL, Java, Android, iOS, Swift
  • Mobile Lead | Senior iOS Engineer

    2017 - 2018
    YardClub (was acquired by Caterpillar)
    • Designed and developed, in half the time allotted, a fleet application that allowed users to manage their fleet of heavy equipment, view high-level analytics, and get notified regarding any potential fleet issues.
    • Maintained and upgraded the company's aging rental application: an app with Airbnb-like listings for heavy construction equipment.
    • Integrated four generations of codebases, including that of two foreign contractors—resulting in a clean, maintainable codebase.
    Technologies: Agile, Firebase, Xcode, OAuth, REST, PostgreSQL, iOS, Objective-C, Swift
  • Co-founder | Lead Engineer

    2013 - 2016
    • Co-led a small team to design and implement a web-based, group coordination application that utilizes a PostgreSQL database supporting a Grails-based server with an AngularJS-based client.
    • Managed a remote quality assurance team to provide detailed testing results in time with a rapid development and deployment schedule.
    • Worked in coordination with the marketing team to provide an agile-based user-feedback—a development cycle that resulted in an efficient and responsive product development strategy that was in line with users’ needs.
    Technologies: Agile, Firebase, PostgreSQL, MongoDB, Angular, Grails
  • Senior Software Engineer

    2015 - 2015
    • Designed and developed Ipsy’s iOS mobile application, that services thousands of users and receiving an overall five-star rating (a link to the app can be found in my Experience section).
    • Created a novel interface allowing the mobile and web applications to seamlessly communicate.
    • Assisted with mentoring junior engineers by teaching them proper engineering techniques and assimilating them into Ipsy's culture.
    Technologies: Swift, Agile, Firebase, Xcode, iOS SDK, Angular, Grails, Objective-C, iOS, Java, Android
  • Development Engineer

    2006 - 2011
    Applied Signal Technology
    • Designed, implemented, and maintained a Qt-based graphics library that allowed the user to view and manipulate numerous STM- 256 signals down to the sub-VGC level in real-time.
    • Developed and maintained a multithreaded C++ client/server application for signal analysis to continually meet the customer’s evolving requirements. Communication between the client and the server was done via CORBA.
    • Manipulated SDH and PDH signal structures to perform various operations on the information in the data streams.
    • Conducted design and code reviews for all team members in an effort to both improve the product as well as guide junior members of the team.
    Technologies: Agile, CORBA, Qt, C++


  • Cat® App: Fleet Management (Development)

    Efficient equipment management starts with the Cat® app. Track the location and health of your equipment, order service and parts, and increase utilization in just a few taps. Staying on top of your fleet has never been easier.

    I was responsible for leading the team as well as personally responsible for 100% of the iOS codebase.

  • Ipsy's iOS Mobile Application (Development)

    I designed and developed Ipsy’s iOS mobile application that services thousands of users and received an overall 5-star rating.

  • Write Once, Deploy Everywhere: When to Go Native? (Publication)
    Writing multiple native applications for different mobile platforms can be a daunting task, but taking a non-native approach comes with pitfalls of its own. In this article, Toptal Mobile Developer Joel Frank outlines the concept of Write Once, Deploy Everywhere (WODE) and explains how to choose the right development path for your project.


  • Languages

    Swift, Objective-C, Java, C++, C, Groovy, HTML, CSS, Kotlin, JavaScript, Python
  • Frameworks

    Swinject, iOS SDK, UIkit, Core Bluetooth, iOS SceneKit, GameKit, Angular, Android SDK, Qt, AngularJS, ARKit, Grails, React Native
  • Libraries/APIs

    HealthKit, Core Image, AVKit, Firebase iOS SDK, Firebase Android SDK, SpriteKit, ReactiveX, RxSwift, CocoaPods, Facebook API, Fitbit API, Node.js
  • Tools

    Apple HealthKit, Xcode, Interface Builder, Auto Layout, Firebase Analytics, Fastlane, Android Studio, Photoshop CS6, IntelliJ, Sirikit, Firebase Cloud Messaging (FCM)
  • Paradigms

    Model View Viewmodel (MVVM), MVC Design, Model View Controller (MVC), Model View Intent (MVI), Model View Presenter (MVP), Requirements Analysis, Agile, Dependency Injection, Concurrent Programming, REST
  • Platforms

    Bitrise, Mobile, iOS, Android, Firebase, iAd, Amazon Web Services (AWS), Unix
  • Storage

    Cloud Firestore, Firebase Realtime Database, PostgreSQL, MongoDB, MySQL, Realm
  • Other

    APIs, Models, Model View, SDKs, Carthage, Code Architecture, Agile Sprints, AVFoundation, Architecture, Technical Leadership, Leadership, Health, Mobile Streaming, AWS, Firebase Cloud Functions, CORBA, OAuth


  • Ph.D. in Computer Science
    2011 - 2017
    University of California, Santa Cruz - Santa Cruz, CA, USA
  • Master of Science (MSc) degree in Computer Science
    2006 - 2008
    San Jose State University - San Jose, CA, USA
  • Bachelor of Science (BSc) degree with honors in Computer Science
    2001 - 2006
    San Jose State University - San Jose, CA, USA

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