toptal.com
Contact us: +1.888.604.3188
Stefan Progovac, Software Developer in Miami Beach, FL, United States
Stefan Progovac

Software Developer in Miami Beach, FL, United States

Member since January 31, 2015
Stefan is a highly skilled iOS developer with a master's degree in physics. He loves both technological and artistic sides of software engineering. He has had the pleasure to work on some popular enterprise-level apps used by millions of people for companies like Target, Best Buy, and Roomi. He believes that app development is truly an art.
Stefan is now available for hire
Hire Stefan

Portfolio

Experience

Location

Miami Beach, FL, United States

Availability

Part-time

Preferred Environment

Swift, Objective-C

The most amazing...

...app I've developed was Cartwheel for Target, an app that has touched so many people.

Employment

  • Senior iOS Developer

    2015 - 2020
    AutoLoop, LLC
    • Leveraged gelocation for marketing purposes.
    • Wrote an entire UI and unit test suite.
    • Wrote scripts in Fastlane to fully automate the release—perform screenshots, run all tests, and make releases.
    • Built custom UI and animation.
    • Wrote an app to facilitate the check-in procedure for car dealers.
    Technologies: Objective-C

  • iOS Developer

    2019 - 2019
    Latch
    • Helped with the reskinning of the UI for the release.
    • Worked on debugging issues with Bluetooth connection using BLE protocol.
    • Created custom UI components, like piecharts using Core Graphics.
    Technologies: Bluetooth LE, iOS, Swift, Core Data, Carthage

  • Senior iOS Developer

    2015 - 2019
    Max2, Inc.
    • Worked on a payment module that required Bluetooth interfacing with hardware.
    • Formatted ISO 8583 messages intended to securely process payments.
    • Developed a chat module leveraging web sockets.
    • Worked with remote and in-app notifications.
    • Worked with Twitter, FB, and Instagram SDKs. The app promotes social media interactivity.
    • Built a custom UI.
    • Wrote an app that allows users to search for, view, and rate venues as well as purchase items and do transactions.
    Technologies: Swift, Objective-C

  • iOS Developer

    2015 - 2015
    Stand Technologies
    • Oversaw this project for a small stand-up company from development to release on the App Store.
    • Implemented push notifications, including writing server-side code.
    • Created a custom networking layer, including efficient categories for image caching and setting UIImageViews, with the ability to cancel or reuse requests if the UIImageView would happen to be reused (such as in a reusable cell) using associated objects.
    • Used Facebook APIs for login.
    • Created a custom newsfeed using dynamic row heights for added flexibility.
    Technologies: Swift

  • Senior iOS Developer

    2015 - 2015
    Roomi
    • Integrated Parse and Layer to build native chat into the app.
    • Worked with Core Animation, Core Text, and CALayer to customize the user experience.
    • Used advanced techniques, such as object swizzling, to override default behavior and enhance functionality.
    • Worked with Parse's cloud and developed and maintained scripts in JavaScript.
    • Worked extensively with push notifications.
    Technologies: Objective-C, Parse, Layer

  • iOS Developer

    2014 - 2015
    Best Buy
    • Redesigned and rewrote the entire Best Buy app in Swift.
    • Architected the app based on the VIPER paradigm.
    • Made use of new Apple technologies such as app extensions and their widgets, primarily for advertisements.
    • Experimented with iBeacons. Best Buy was one of the first stores to embed iBeacons into their department store lighting.
    • Began working on Apple Pay for a more seamless checkout experience using the Best Buy app.
    • Replaced the zBar scanner with a native Apple scanner for barcodes.
    • Implemented fast image caching across the application.
    Technologies: Swift

  • Senior iOS Developer

    2014 - 2014
    ConXus Lochinvar
    • Redesigned the UI to look appropriate for the iPhone. Previous developers had only paid attention to the iPad.
    • Gained extensive experience with auto layouts of all forms.
    • Worked with the Microsoft Cloud and Azure.
    Technologies: iOS

  • iOS Developer

    2013 - 2014
    Target (Cartwheel)
    • Worked on implementing a highly automated environment. Employed a dedicated Jenkins server and Xcode bots and hooks so every Git checkin for the QA would get the latest build to Test Flight.
    • Worked with Crashlytics for bug tracking.
    • Worked with true Agile methodologies and Jira for efficient work progress.
    • Worked extensively with PassKit and CocoaPods.
    • Made extensive use of OAuth tokens to guard sessions for items added to cart, as well saved payment information (each having their own tokens).
    • Used Google Postman to debug and document RESTful APIs.
    Technologies: iOS, Objective-C

  • iOS Developer

    2012 - 2013
    Rockwell Collins
    • Made extensive use of MapKit and Waypoints for plotting airplane itineraries.
    • Made a custom calendar from UICollection View.
    • Made extensive use of core data as a kind of cache for data, including using helpful third-party tools like Mogenerator.
    • Implemented extensive security features, such as storing in the keychain and various hashing and encryption algorithms.
    • Used regular expressions for input validation to prevent SQL injections.
    Technologies: iOS, Objective-C

Experience

  • Cartwheel App (Development)

    A social savings app for Target. I was one of two developers who rewrote Cartwheel away from the original code base, which was owned by Deloitte. Cartwheel is used by millions of people across the USA.

  • Best Buy (Development)
    https://itunes.apple.com/us/app/best-buy/id314855255?mt=8

    This is the Best Buy store shopping experience app. I was the lead architect in the Swift redesign of the Best Buy app, employing the VIPER paradigm. The project included experimentation with iBeacons and Apple Pay.

  • SmartLane (Development)
    https://itunes.apple.com/us/app/smartlane/id686173091?mt=8

    A dealership app that I am currently maintaining for AutoApp. It is used in Mercedes and Toyota dealerships all across the USA. It allows you to check in and have service on your car, all from the convenience of an iPad.

  • Ascend Flight Manager (Development)
    https://itunes.apple.com/us/app/flight-manager/id469557418?mt=8

    Manage your private jet with this convenient app! This app allows you to create custom flight plans for your private jets. I was the sole developer on this app. It features an immense focus on security, as his clientele base consists of executives for large companies like Coca Cola. I explored the depths of security provided by the Apple OS and was tasked with adding my own custom security options.

  • Roomi (Development)
    https://roomiapp.com

    A app to help people find roommates in cash-expensive markets such as New York City and San Francisco, this app facilitates in-app chat (which I personally developed), paying rent through the app, and browsing room listings

  • STAND (Development)

    A social fundraising app to help motivate positive change around the world. Start your own fundraising stands and get your Facebook friends as well as others in the loop. Watch as money is raised for your favorite projects.

  • Senior Software Developer for Max2 (Development)

    Developed their merchant facing app for iOS in Swift. Worked on the payment module, leveraging Bluetooth, securely formatting messages (using ISO 8583) to securely process payments, app notifications, leveraging websockets, and more.

  • LATCH (Development)
    https://apps.apple.com/us/app/latch-app/id1062355375

    Developed the UI for Latch App including app interfaces (via BLE protocol) with hardware locks that control access to doors for individual customers and businesses alike. I was part of the team that redesigned and implemented a re-branding and new UI.

  • iOS Animation and Tuning for Efficiency (Publication)
    https://www.toptal.com/ios/ios-animation-and-tuning-for-efficiency
    Smooth animations and flawless transitions are key to perceived performance in modern mobile applications. Without the right tools, tuning iOS animation for efficiency can be a challenge in itself. In this article, Toptal engineer Stefan Progovac demonstrates the role of Instruments, a sophisticated set of performance profiling tools for iOS, discussing how they can help you understand animation performance bottlenecks and some strategies for working around them.

Skills

  • Languages

    Swift, XML, Objective-C, Java, JavaScript, Python

  • Frameworks

    OAuth 2, AFNetworking, Core Data

  • Libraries/APIs

    CocoaPods, Parse SDK, Layer API, Apple Maps API, Kiwi, Mantle, Google API, Facebook SDK, jQuery

  • Tools

    Hockey SDK, Crashlytics, GitHub, Git, Jira, Xcode, Slack, Apple Push Notifications, Suds, Pivotal Tracker, Asana

  • Paradigms

    Agile Software Development, Mobile Development

  • Platforms

    iOS, Apple Watch, Firebase

  • Storage

    JSON

  • Other

    OAuth, Geolocation, Programming, Freelance, IT

Education

  • Master of Science degree in Physics
    2009 - 2012
    University of California San Diego - San Diego, USA
  • Bachelor of Science degree in Mathematics
    2005 - 2009
    Michigan State University - East Lansing, USA

To view more profiles

Join Toptal
Share it with others
Hire the top 3% of freelance developers TM