Joel is available for hire

Joel Frank

Verified Expert in Engineering

Mobile Application Developer

Location

São Tomé de Covelas, Portugal

Toptal Member Since

December 26, 2019

With a PhD 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.

Portfolio

Kilsar, Inc.

Swift, iOS, ARKit, Augmented Reality (AR), Mobile Apps, SwiftUI, Node.js...

Caterpillar

Front-end, Full-stack, iOS, Heroku, Amazon Web Services (AWS), Android, Kotlin...

Bleu Tech Enterprises, Inc.

Bluetooth, Bluetooth LE, iOS, Android, Universal Windows Platform (UWP)...

Experience

iOS - 17 years Firebase - 10 years Amazon Web Services (AWS) - 8 years Swift - 7 years SOLID Principles - 6 years React Native - 3 years Augmented Reality (AR) - 2 years Node.js - 1 year

Availability

Part-time

Preferred Environment

Android, iOS, Mobile App Development, User Experience (UX), Flutter, SwiftUI, SOLID Principles

The most amazing...

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

Work Experience

Lead Augmented Reality Engineer

2022 - PRESENT

Kilsar, Inc.

Architected and implemented an iOS-based augmented reality training application that allowed for both solo AR sessions and a shared AR experience by embedding the AR session into a multi-person VTC (video teleconferencing) call.
Led the joint front- and back-end team effort to define the system architecture's microservices for a modular, reusable, performant, and cost-efficient back end.
Worked to translate the company's strategic roadmap from long-term deliverables down to day-to-day operations for the mobile team while reliably meeting deadline after deadline.
Maintained the team's focus on quality by continually adapting, improving, and polishing the designs under changing requirements.

Technologies: Swift, iOS, ARKit, Augmented Reality (AR), Mobile Apps, SwiftUI, Node.js, Serverless, AWS Lambda, Front-end Development, Mobile Development, Mobile UI, Mobile UX, Video Streaming, Networking, VoIP, Auth, Audio Streaming, Location Services, Mobile Architecture, GPS, Internet of Things (IoT), Amazon Web Services (AWS), Streaming, Apps, iTunes Connect, TypeScript, Back-end, Full-stack, Software Design, Mobile Applications, Flutter, Dart, SOLID Principles, DevOps, Serverless Framework, Amazon Cognito, Identity & Access Management (IAM), Keychain, Application Security, Security, SSL, SSL Certificates

Lead Mobile Engineer

2018 - 2022

Caterpillar

Managed the small but highly effective engineering team that was able to change how a Fortune 50 company creates and maintains the software.
Created the core fleet application that became The Cat App: Caterpillar's central flagship mobile application. https://apps.apple.com/us/app/cat-app-fleet-management/id1258931644.
Developed and performed a side-by-side evaluation of a single application against three frameworks: KMM (Kotlin Multiplatform Mobile) with Native SwiftUI, React Native, and Flutter.
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.
Transformed the team's strategic roadmap into actionable sprint plans while meeting the ever-changing requirements of the company's product owners and stakeholders.

Technologies: Front-end, Full-stack, iOS, Heroku, Amazon Web Services (AWS), Android, Kotlin, Kotlin Multiplatform Mobile (KMM), Architecture, Firebase, Swift, Java, React, React Native, Mobile, Fastlane, Core Data, Core Animation, REST APIs, UX Design, Team Leadership, UIKit, Model View ViewModel (MVVM), Unit Testing, UI Testing, Apple Design, JavaScript, TypeScript, ARKit, Bluetooth, Bluetooth LE, Mobile App Development, Redux, Azure Cloud Services, API Integration, SwiftUI, Azure DevOps, Dashboards, Figma, User Experience (UX), UI Animation, User Interface (UI), Test-driven Development (TDD), Git, Core Location, XML Interface Builder (XIB), AVFoundation, Combine, Mobile Apps, Scrum, GitHub, JSON, XML, Technical Leadership, CI/CD Pipelines, Jira, Augmented Reality (AR), iOS Native Libraries, Design Patterns, Mapbox, Node.js, Azure, Technical Architecture, Leadership, Front-end Development, Mobile Development, Mobile UI, Mobile UX, RxSwift, Video Streaming, Networking, Google Cloud Platform (GCP), iPad, Amazon Transcribe, Auth, Python, Location Services, Mobile Architecture, GPS, Apps, iTunes Connect, Back-end, Software Design, Mobile Applications, Flutter, Dart, SOLID Principles, DevOps, Serverless Framework, Amazon Cognito, Identity & Access Management (IAM), HIPAA Compliance, Keychain, Application Security, Security, SSL, SSL Certificates

Lead Mobile BLE Engineer

2020 - 2021

Bleu Tech Enterprises, Inc.

Designed and implemented core BLE libraries for merchant and client, iOS, Android, and UWP, to facilitate encrypted payment transactions via Bluetooth.
Optimized the BLE bandwidth while allowing messages of arbitrary size in multiple communication channels.
Coordinated with a diverse team spanning three continents to meet all project milestones ahead of schedule.

Technologies: Bluetooth, Bluetooth LE, iOS, Android, Universal Windows Platform (UWP), Elliptic Curve Cryptography, Swift, Java, C#, SDKs, Mobile, Fastlane, REST APIs, Team Leadership, Unit Testing, WebSockets, Mobile App Development, API Integration, SwiftUI, User Experience (UX), Test-driven Development (TDD), Git, XML Interface Builder (XIB), Mobile Apps, Payment Gateways, Payment APIs, Scrum, GitHub, JSON, XML, Technical Leadership, CI/CD Pipelines, Jira, iOS Native Libraries, Design Patterns, Cryptocurrency Wallets, Mobile Wallet, Fintech, Node.js, Technical Architecture, Leadership, Front-end Development, Mobile Development, Mobile UI, Mobile UX, eCommerce, RxSwift, Networking, Google Cloud Platform (GCP), iPad, Auth, Python, Location Services, Mobile Architecture, GPS, Internet of Things (IoT), Amazon Web Services (AWS), Apps, iTunes Connect, Software Design, Mobile Applications, SOLID Principles, DevOps, Serverless Framework, Amazon Cognito, Identity & Access Management (IAM), PCI Compliance, Keychain, Application Security, Security

CTO | Lead Engineer

2020 - 2021

Dr Lullaby

Assisted in writing research grant proposals for the NSF, documenting the application's innovative approaches toward sleep therapy.
Revamped the existing system architecture to improve performance, maintainability, and scalability.
Contributed to guide the long-term vision of the project.

Technologies: Front-end, iOS, Android, Back-end, Full-stack, Reinforcement Learning, Swift, Swing, Java, Objective-C, Architecture, Mobile, Fastlane, Core Animation, REST APIs, UX Design, Team Leadership, CTO, UIKit, Model View ViewModel (MVVM), Unit Testing, UI Testing, WebSockets, Apple Design, Mobile App Development, API Integration, User Experience (UX), UI Animation, User Interface (UI), Test-driven Development (TDD), Git, Core Location, XML Interface Builder (XIB), Mobile Apps, Payment APIs, Scrum, GitHub, JSON, XML, Technical Leadership, CI/CD Pipelines, iOS Native Libraries, Design Patterns, Mobile Banking, Technical Architecture, Leadership, Front-end Development, Mobile Development, Mobile UI, Mobile UX, Networking, iPad, Auth, Location Services, Mobile Architecture, Apps, iTunes Connect, Mobile Applications, Flutter, SOLID Principles, HIPAA Compliance, Keychain, Application Security, Security

Co-founder | Lead Engineer

2013 - 2016

GroupTing

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 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, Mobile, CocoaPods, Facebook API, CSS, MySQL, iOS Native Libraries, Design Patterns, Mobile Development, Mobile UI, Mobile UX, eCommerce, Networking, Google Cloud Platform (GCP), Auth, Location Services, Mobile Architecture, Amazon Web Services (AWS), Apps, iTunes Connect, Software Design, Mobile Applications, SOLID Principles, Keychain, Application Security, Security

Senior Software Engineer

2015 - 2015

Ipsy

Designed and developed Ipsy’s iOS mobile application that services thousands of users and receives 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, Objective-C, iOS, Java, Android, Mobile, CocoaPods, Facebook API, CSS, MySQL, Payment Gateways, Payment APIs, iOS Native Libraries, Design Patterns, Fintech, Mobile Development, Mobile UX, Android API, Auth, Location Services, Mobile Architecture, Apps, iTunes Connect, Full-stack, Software Design, Mobile Applications, PCI Compliance, Security

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, C++, Networking, Mobile UX, Android API, Telecommunications, VoIP, Mobile Architecture, iTunes Connect

Experience

Cat® App: Fleet Management

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

https://apps.apple.com/us/app/ipsy-beauty-makeup-tips/id1016673544

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

Draw Together

A real-time collaborative drawing application that allowed multiple artists to work together, share ideas, and create artwork. The key technical challenge the application overcomes is the dynamic drawing stack becoming too large as more and more edits and changes are done to the drawing, which would otherwise make the application slow down and become non-performant.

Risk Runner

A multiplayer and AI-based Risk application (en.wikipedia.org/wiki/Risk_(game)) that integrated the user's movement and steps to determine their attack power during the game. The application supported both HealthKit as well as Fitbit.

Publication

Write Once, Deploy Everywhere: When to Go Native?

https://www.toptal.com/app/native-vs-hybrid-apps-pros-and-cons

Skills

Languages

Swift, JavaScript, XML, Dart, Java, C++, Python, Objective-C, HTML, CSS, Kotlin, TypeScript, GraphQL, C#

Frameworks

iOS SDK, UIKit, Core Bluetooth, iOS SceneKit, GameKit, Flutter, SwiftUI, Core Location, Android SDK, React Native, ARKit, Core Data, Redux, Combine, Serverless Framework, Swing

Libraries/APIs

HealthKit, Core Image, AVKit, Firebase iOS SDK, Firebase Android SDK, SpriteKit, Core Animation, REST APIs, iOS Native Libraries, Auth, ReactiveX, CocoaPods, Facebook API, Fitbit API, RxSwift, Android API, Node.js, React, Core Graphics

Tools

Apple HealthKit, Xcode, Interface Builder, Auto Layout, Firebase Analytics, Git, XML Interface Builder (XIB), iTunes Connect, Fastlane, Android Studio, Sirikit, Firebase Cloud Messaging (FCM), Figma, GitHub, Jira, Amazon Transcribe, Amazon Cognito

Paradigms

Model View ViewModel (MVVM), MVC Design, Model View Controller (MVC), Model View Intent (MVI), Model View Presenter (MVP), Requirements Analysis, Agile, UX Design, Unit Testing, Test-driven Development (TDD), Scrum, Design Patterns, Mobile Development, Dependency Injection, Concurrent Programming, Azure DevOps, HIPAA Compliance, REST, DevOps

Platforms

Bitrise, Mobile, iOS, Android, Firebase, Amazon Web Services (AWS), iAd, Bluetooth LE, Mapbox, Google Cloud Platform (GCP), Keychain, Unix, Heroku, AWS Lambda, Universal Windows Platform (UWP), Azure

Storage

Cloud Firestore, Firebase Realtime Database, MySQL, JSON, PostgreSQL, MongoDB, Realm, Azure Cloud Services

Other

APIs, Models, Model View, SDKs, Carthage, Code Architecture, Agile Sprints, Architecture, Technical Leadership, Leadership, Bluetooth, Team Leadership, UI Testing, Apple Design, Mobile App Development, API Integration, User Experience (UX), UI Animation, User Interface (UI), Mobile Apps, SOLID Principles, Front-end Development, Mobile UI, Mobile UX, iPad, Location Services, Mobile Architecture, Apps, Software Design, Mobile Applications, Mobile Streaming, Firebase Cloud Functions, AVFoundation, Networking, Full-stack, CTO, WebSockets, Payment Gateways, Payment APIs, CI/CD Pipelines, Augmented Reality (AR), Lambda Functions, Serverless, Fintech, Mobile Banking, Technical Architecture, eCommerce, Video Streaming, VoIP, GPS, Internet of Things (IoT), Streaming, Identity & Access Management (IAM), Application Security, Security, OAuth, Kotlin Multiplatform, Front-end, Back-end, Reinforcement Learning, Elliptic Curve Cryptography, Kotlin Multiplatform Mobile (KMM), Animation, Algorithms, Google Fit, SVG Animation, Dashboards, Cryptocurrency Wallets, Mobile Wallet, Audio Streaming, PCI Compliance, SSL, SSL Certificates

Industry Expertise

Telecommunications

Education

2011 - 2017

PhD in Computer Science

University of California, Santa Cruz - Santa Cruz, CA, USA

2006 - 2008

Master of Science (MSc) Degree in Computer Science

San Jose State University - San Jose, CA, USA

2001 - 2006

Bachelor of Science (BSc) Degree with Honors in Computer Science

San Jose State University - San Jose, CA, USA

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