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Zoltan Varadi

Zoltan Varadi

Szeged, Hungary
Member since September 15, 2015
As a user experience enthusiast, Zoltan's greatest strength as an engineer is his precise design implementation. He has a positive attitude and an open mindset that enable him to bring the best quality projects to life. Zoltan's experience in maintaining a relationship with customers and managing team workflow help him to provide the best overall value to his team.
Zoltan is now available for hire
  • Interface Builder, 7 years
  • iOS, 7 years
  • Auto Layout, 6 years
  • Sketch, 3 years
  • Swift, 3 years
  • Core Location, 3 years
  • Core Data, 3 years
Szeged, Hungary
Preferred Environment
XCode, Swift, Interface Builder, GitHub
The most amazing...
...feeling was receiving written consent from NASA to publish my pet project, Apollo Archive to the iTunes App Store.
  • iOS Developer Ltd (via Toptal)
    2016 - 2016
    • Created a pixel perfect design implementation that scales well on all iPhone devices for new features.
    • Identified performance issues causing high network consumption and fixed them.
    • Created reusable components in Swift, merged it in the Objective-C based environment.
    • Simplified the app by removing unused features, merging menu items together, adding an in-app web browser, and improving the on-boarding flow.
    Technologies: Objective-C, Swift, Storyboard, Interface Builder, RESTful APIs
  • iOS Developer
    Kalon Creative (via Toptal)
    2016 - 2016
    • Upgraded an existing iOS app from Swift 1.2 to Swift 3.
    • Replaced deprecated function calls with their newest versions.
    • Added minor changes requested by the client.
    • Versioned the source code in each step of the upgrade process under separate branches using git.
    Technologies: Swift 1.2, Swift 3, Foundation, UIKit, Alamofire
  • Senior iOS Developer
    Perchwell (via Toptal)
    2015 - 2016
    • Created a pixel perfect design implementation that scales well on all iPhone devices.
    • Identified performance issues causing choppiness in the user experience and fixed them.
    • Optimized memory and CPU time management.
    • Implemented complex data visualization using 15+ different chart types.
    Technologies: Swift, Interface Builder, Auto Layout, Alamofire, SDWebImage, iOS Charts, SnapKit, Mixpanel, Fabric
  • Lead iOS Developer
    Red Steed Studios
    2013 - 2015
    • Learned how to divide projects into tangible tasks and how to simplify and execute these projects while allowing space for changes.
    • Used several third party services, such as Facebook, Google, Imgur, Amazon S3,, etc.
    • Took part in projects actively as a Developer and as a Development Team Leader.
    Technologies: Objective-C, Core Data, Interface Builder, Auto Layout, Protocol Buffers, REST, TLS, embedded web technologies, Location Services
  • iOS Developer
    Pronovix Hungary
    2012 - 2014
    • Worked as a Full-stack Developer.
    • Maintained a relationship with clients.
    • Managed project requirements such as design, implementation, testing, and follow-up.
    • Developed an iOS application with its PHP based back-end for a coffee shop.
    • Created an application for mechanical watch owners to keep track of their device's accuracy and set their time using atomic clocks.
    Technologies: Objective-C, Core Data, Drupal, REST, JSON, NTP, Git,
  • C++ Developer
    GE Healthcare
    2010 - 2012
    • Implemented clinical research applications to find lung and liver cancer in CT images.
    • Improved the speed of a tumor searching algorithm by 90%.
    • Became co-author of a worldwide patented workflow for finding tumors in the liver organ in CT images.
    • Created and implemented an algorithm for better visualizing cancerous areas in the lung area in CT images.
    Technologies: C++, Image Processing
  • Apollo Archive (Development)

    Apollo Archive is an app for space enthusiasts. It helps its users to browse through all images taken during the Apollo missions and enjoy them in high resolution. What makes this app special to me is the written consent I received from NASA to publish the app freely to the app store.

    With this app, I wasn't exclusively the developer, however I did the UI/UX design myself. My goal was to gain first-hand experience with product development from ideation to production, and to become familiar with all aspects of a product's lifecycle.

  • PetrolPrices (via Toptal) (Development) is the largest fuel price comparison service in the United Kingdom. I had the privilege to improve the existing app's functionality, and increase its performance and stability.

  • NYC Apartments by Perchwell (via Toptal) (Development)

    Perchwell is an iOS application for finding real-estate in Manhattan, New York. It offers a great interface for filtering suitable properties, comparing them, and calculating expenses. The application also helps to analyze the real-estate market with various charts.

  • Dryft (Development)

    Dryft is an application for hikers who don't want to get lost when they go into the wilderness. It keeps a constant record of their whereabouts, notifies them if they have gone too far or too long, and guides them back to where they started.

  • Ntice (Development)

    As a consultant, helped the Ntice team to improve their existing application.

  • My first international presentation session at iOSDevUK (Other amazing things)

    I had the honor of speaking about third party tools and practices at one of Europe's biggest conference.

  • Languages
    Swift, Swift 4, Swift 3, Swift 2, Objective-C, C++, Java, JavaScript
  • Frameworks
    Core Location, Core Data
  • Libraries/APIs
    MapBox iOS SDK, Google Maps SDK, Core Animation, Google Maps Premium Roads API, Fabric, Flickr API, iOS Charts, Firebase Web SDK, Facebook iOS SDK, Facebook API
  • Tools
    Auto Layout, Sketch, Interface Builder, Git, Crashlytics, Fastlane, Pivotal Tracker, Adobe Photoshop, Adobe Illustrator
  • Paradigms
    Responsive Development, Agile Software Development
  • Platforms
    Back4App, iOS, Parse
  • Other
    Pixel Perfect, RESTful APIs, User Interface (UI), User Experience (UX), Medical Imaging, 3D Image Processing, Image Processing, Protocol Buffers
  • Various Certificates in Aerospace Engineering
    MIT, ESA - Online
    2016 - 2016
  • Master's degree in Computer Engineering and Image Processing (unfinished)
    University of Szeged - Szeged, Hungary
    2011 - 2013
  • Bachelor's degree in Computer Engineering
    University of Szeged - Szeged, Hungary
    2006 - 2011
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