Oaca Stefanita, Developer in Craiova, Romania
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Oaca Stefanita

Verified Expert  in Engineering

iOS Developer

Craiova, Romania
Toptal Member Since
January 31, 2020

With over nine years of iOS experience, Stef's worked on all Apple products—iPhone, iPad, Mac, Apple Watch, Apple TV—and has used every Apple technology out there (Core ML, ARKit, RealityKit, and many others). He can work with any SDK, API, or library and develop amazing apps taking advantage of Apple's ecosystem. Stef is always up to date with the best practices, the newest technologies, the latest security updates, and the latest rumors regarding the industry's next big thing.


Freelance Client
Swift, SwiftUI, Video Streaming, APIs, tvOS, tvOS UI, Apple TV, Core Data
Contarini Ventures, LLC
iOS, Swift, Networking, iOS Camera, Video Processing, App Store, Subscriptions...
Swift, Xcode, Figma, Augmented Reality (AR), ARKit, UIKit, iOS, REST, APIs




Preferred Environment

Android Studio, Adobe Photoshop, iOS, MacOS, Xcode, Figma, iPad, Apple TV, Apple Watch, iPhone

The most amazing...

...app I've developed was an augmented reality application which, after taking a personality test, created a unique flower and presented it in AR.

Work Experience

Senior Apple TV Developer

2023 - 2024
Freelance Client
  • Developed a tvOS app that displays and allows navigation through lists of movies and TV shows.
  • Developed a tvOS app Top Shelf extension that allows users to preview their most important titles lists.
  • Oversaw the entire development process from the design phase all the way to an MVP.
Technologies: Swift, SwiftUI, Video Streaming, APIs, tvOS, tvOS UI, Apple TV, Core Data

iOS Developer

2022 - 2023
Contarini Ventures, LLC
  • Updated and improved an app with a large user base called Leap Second.
  • Created new and customizable user flows within the old UI.
  • Oversaw new releases, making sure all the new changes were working properly.
  • Integrated new SDKs for A/B testing, analytics, purchases, and customizable paywalls, among others.
Technologies: iOS, Swift, Networking, iOS Camera, Video Processing, App Store, Subscriptions, SwiftUI, Firebase, Firebase Authentication, iOS Native Libraries, Git, Slack, Mobile App Design

Augmented Reality iOS Developer

2022 - 2022
  • Developed an iOS app that generates and presents a unique flower in AR based on a personality test from the user.
  • Created the project from scratch using Swift, UIKit, ARKit, and a REST API.
  • Worked side by side with the Android team, design team, and client.
Technologies: Swift, Xcode, Figma, Augmented Reality (AR), ARKit, UIKit, iOS, REST, APIs

iOS Developer

2021 - 2022
Contarini Ventures, LLC
  • Updated and improved an app called Moment Garden with a large user base.
  • Tracked and fixed existing bugs and issues using Linear and Notion, among other tools.
  • Proposed improvements and integrated new SDKs in the old codebase.
Technologies: iOS, Swift, Networking, App Store, Subscriptions, Firebase, Firebase Authentication, iOS Native Libraries, Git, Slack, REST, APIs

Flutter Developer

2021 - 2021
Boohead Inc
  • Developed a cross-platform app using Flutter, allowing kids to draw shapes using their fingers.
  • Created a shape-drawing algorithm that is both fast and RAM effective.
  • Built everything from scratch to the final release.
Technologies: Flutter, Android, iOS, Dart

Artificial Intelligence iOS Developer

2021 - 2021
  • Developed an iOS app that used a TensorFlow AI model in order to detect objects seen with the camera.
  • Worked as a part of multi developers iOS team, my work was only related to the integration of the AI model.
  • Created a proof of concept project using Core ML (Apple's Machine Learning tool).
Technologies: TensorFlow, TensorFlow Lite, iOS, Swift, Xcode, iPhone, iPad, Artificial Intelligence (AI), iOS Camera, iOS Video, Figma, iOS SDK, Minimum Viable Product (MVP), Agile, iOS Native Libraries, Git, Slack

Augmented Reality iOS Developer

2020 - 2020
Coventry University
  • Developed an iOS-augmented reality application for displaying university projects.
  • Created a Fibonacci-based algorithm for displaying the project in AR in a sphere shape.
  • Implemented the project using Swift and ARKit and followed the provided design.
Technologies: ARKit, Swift, Xcode, iOS, iPhone, iPad, iOS Camera, iOS Video, Figma, iOS SDK, Minimum Viable Product (MVP), Agile, Augmented Reality (AR), AR Interfaces, iOS Native Libraries, Git, REST, APIs

Senior iOS Developer

2020 - 2020
  • Helped with the final part of the development process.
  • Tracked down and fixed bugs, implemented UI improvements, and improved the architecture.
  • Clarified how the app works in detail with the client as well as estimating server costs.
Technologies: iOS SDK, Stripe, Geolocation, Xcode, UIKit, Firebase, Swift, iOS, iPhone, Firebase Authentication, iOS Native Libraries, Git

Augmented Reality iOS Developer

2020 - 2020
  • Developed an app that draws in 3D space using Apple's ARKit.
  • Developed features such as freehand drawing, line drawing, extrusion of 2D shapes, detection of vertical and horizontal planes, and snap drawing to detected planes.
  • Created the entire project from scratch, establishing architecture and providing time estimates.
  • Extended the app to multiuser shared sessions with a synchronization mechanism and undo feature.
Technologies: iOS SDK, iPad, iPhone SDK, iOS SceneKit, Metal, Adobe Experience Design (XD), Project Management, Xcode, ARKit, Swift, iOS, iPhone, iOS Native Libraries, Git, Mobile App Design

CTO | Co-founder

2015 - 2020
Codapper Software
  • Built applications with features including live audio and video calls, live chat, complex animations, push notifications, in-app purchases, and subscriptions.
  • Developed complex project architectures from scratch.
  • Handled the entire lifecycle of the project from first engaging the client to the final delivery and the maintenance that is crucial in the first weeks after the launch of the product.
  • Developed applications for macOS, watchOS, and tvOS besides the iOS applications.
  • Created stunning applications with augmented reality features using ARKit.
  • Used the whole range of device features from GPS, biometrics, and accelerometers to Bluetooth file transfers.
Technologies: iOS Video, iOS Camera, iOS SDK, iPad, iPhone SDK, Apple Push Notifications, REST, Apple Subscriptions, Sketch, Flinto, Adobe Photoshop, iOS SceneKit, Agile, Project Management, WatchOS, tvOS, MacOS, iOS, Xcode, XMPP, CocoaPods, Cocoa, UIKit, ARKit, Swift, Objective-C, iPhone, Leadership, Team Management, App Store, Subscriptions, iOS Native Libraries, Jira, Git, Mobile App Design, APIs

iOS Developer

2013 - 2015
Netrom Software
  • Developed various iOS applications for customers with features such as online and offline use, user management, live chats, and multithread image processing.
  • Tracked the project lifecycle using Jira and Agile and became familiar with project management techniques.
  • Oversaw the entire lifecycle of an iOS application from starting the project to uploading to the App Store.
Technologies: iOS Camera, iOS SDK, iPad, UIKit, iPhone SDK, Apple Push Notifications, Xcode, Agile, Swift, iOS, REST, Objective-C, iPhone, Subscriptions, Amazon Web Services (AWS), iOS Native Libraries, Jira, Git, APIs

PPC Revenue

An Objective-C application used for displaying pay-per-click revenue using complex chart animations. There are three versions one for iPhone (and iPad), one for Apple Watch and one for the Mac. It was released to the App Store in 2015.

Spending Tracking

This is a spending tracking application written in Objective-C. It facilitates the management of spending categories and is designed to work offline. The app created charts showing the total spendings of each category. All the data could be exported to various cloud storage services as well reimported. It was released to the App Store in 2015

Online Game

The game allowed users to play truth or dare online with their friends.

It had live chats, live audio, and live video and could accommodate up to six players at the same time. The game used Sockets-based connectivity and XMPP chat. It was written in Swift and was also designed to work offline. It was released to the App Store in 2016

Online Market Place

I built an online market place application written in Swift. It helps users to sell and buy yachts and boat equipment as well as other related miscellaneous accessories and enables bids and trades using your items. It reached #1 in the Caribbean App Store

Human Resources

I developed the entire login and register flow of a human resources application, complete with biometrics authentication, fields autocompletion, and validation. I also handled the monthly subscription flow and maintained the project after launch. It was released to the App Store in 2019

Social Media

I developed a Swift-based social media application with a highly complex UI used to find a significant other as well as build a professional profile. It used GPS location to find users within a radius, it also had a premium subscription level.

CocoaPods Library

A Swift-based CocoaPods library, designed as an easy-to-use tool for communicating via a REST API. It supported iOS, macOS, watchOS, and tvOS and had a demo app for each one as well as unit tests for each functionality.

Sound and Calls Recorder

A Swift-based application for recording sounds and audio calls with features such as audio quality selection, gesture-driven UI, and watchOS extension. The application also had a graphic display of metadata that could be used to add notes and images to the waveform of the audio file.

Files Management

A Swift-based, gesture-driven iOS and watchOS application that allowed the users to organize their files in a folder structure. It included the following features: handling of a trash folder, favorite files, undo feature, and offline use.


A Swift-based app where users could create and participate in real-life events (outings ). Events were either free or paid for by the participants, tickets were generated for each participant, and they were validated by the owner using the app. The user profile was connected to an Instagram account.


Block is an augmented reality 3D drawing app, that allows users to draw shapes using Apple's ARKit, The app allows freehand drawing, line drawing, measuring, plane detection, and drawing on planes. It can be used by multiple users at the same time.

Object Recognition Using Artificial Intelligence

Developed a Swift-based application that used an Artificial Intelligence model (TensorFlow) to detect objects seen by the device's back camera. The application took the camera output, processed it into raw data that the AI could process then took the output of the AI model and used it to display boxes around the discovered objects (using the documentation)
The application had a real-time view of the detected objects.

Leap Second

A Swift-based app for content creation. It creates a collage of photos/live photos that get merged into a video. Users can edit that video and also add background music. New users see a fully customizable onboarding flow (customizable from A/B testing, so it's on the go) and a unique purchase screen.

Moment Garden

A photo-sharing app built using Objective-C and Swift. The application allows parents and grandparents to share albums with total privacy. Users can upload photos and videos, and family members can comment on them.


An augmented reality application that generated a unique 3D flower based on the user's personality test and then presented that flower in augmented reality. Users can see and plant each other's flowers and cross-pollinate them, all in AR.

CU Degree Show

An augmented reality application used to display projects made by students. The application displayed the projects as tiles arranged on a sphere. When a user pointed the camera at one particular project, it would start playing a video.
2010 - 2014

Bachelor's Degree in Computer Science

University of Craiova - Craiova, Romania


Cisco CCNA (Cisco Certified Network Associate)

Cisco at the University of Craiova


Certificate in Advanced English

University of Cambridge


CocoaPods, Apple Subscriptions, iOS Native Libraries, Stripe, TensorFlow


Apple Push Notifications, Firebase Authentication, Git, Jira, Slack, Xcode, Sketch, Flinto, Adobe Photoshop, Adobe Experience Design (XD), Android Studio, Figma


iOS SDK, UIKit, iPhone SDK, Cocoa, iOS SceneKit, Metal, TensorFlow Lite, Core ML, ARKit, SwiftUI, Flutter, Core Data


Swift, Objective-C, C++, Dart


REST, Agile, Mobile App Design


iOS, Firebase, MacOS, WatchOS, tvOS, Twilio, Apple TV, Apple Watch, Amazon Web Services (AWS), Android

Industry Expertise

Project Management


Augmented Reality (AR), iPad, iPhone, APIs, In-app Purchases, App Store, Subscriptions, Minimum Viable Product (MVP), iOS Camera, AR Interfaces, XMPP, Geolocation, Video Streaming, Audio Streaming, iOS Video, Artificial Intelligence (AI), Videos, Leadership, Team Management, Networking, Video Processing, 3D, 3D Modeling, tvOS UI

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