Oaca is available for hire
Hire OacaOaca Stefanita
Verified Expert in Engineering
iOS Developer
Craiova, Dolj County, Romania
Toptal member since January 31, 2020
Bio
With over 11 years of expertise in iOS development, Stef is a dynamic and forward-thinking developer specializing in AI, AR, and cutting-edge native app development. Proficient in Swift, Objective-C, Cocoa, UIKit, and SwiftUI, he also brings extensive experience in cross-platform development using Flutter. Stef’s versatility is evident in his seamless integration of any SDK, API, or library, delivering robust, high-performing code while maintaining full accountability for his work.
Portfolio
Euki, Inc.
Swift, iOS, Mobile App Development, Mobile Applications, Mobile Development...
Freelance Client
Swift, SwiftUI, Video Streaming, APIs, tvOS, tvOS UI, Apple TV, Core Data...
Freelance Clients
Flutter, Android, iOS, Cross-platform, Firebase, WebView, Memory Management
Experience
- iOS - 11 years
- Swift - 9 years
- Apple Subscriptions - 8 years
- In-app Purchases - 8 years
- Artificial Intelligence (AI) - 4 years
- MacOS - 4 years
- WatchOS - 3 years
- tvOS - 3 years
Availability
Part-time
Preferred Environment
iOS, MacOS, Apple TV, Apple Watch, Android, Core ML, Flutter, ARKit, RealityKit, ChatGPT
The most amazing...
...app I've developed was an augmented reality (AR) application which, after taking a personality test, creates a unique flower and presents it in AR.
Work Experience
Mobile Developer
2024 - 2024
Euki, Inc.
- Tracked down and fixed issues that previous developers presented as "unfixable" in a very short time.
- Helped the client to better understand the codebase and its limitations.
- Added new features while maintaining the preexisting architecture and reusing most of the already existing code.
Technologies: Swift, iOS, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps
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, API Integration, Mobile App Development, Large Language Models (LLMs), Mobile Applications, ChatGPT, OpenAI, Mobile Development, Mobile Apps
Senior Flutter Developer
2023 - 2023
Freelance Clients
- Developed a cross-platform app that monitors kidney health.
- Wrote clean Dart code and deployed it on both iOS and Android using Flutter.
- Created the entire project from the start to publishing on the App Store and Google Play.
Technologies: Flutter, Android, iOS, Cross-platform, Firebase, WebView, Memory Management
iOS Developer
2023 - 2023
Da Vinci Eye, LLC.
- Created a POC app from scratch; it presented a humanoid 3D model that the user could move around.
- Tracked down and fixed preexisting issues while also organizing the codebase.
- Worked closely with the client in order to fulfill all the new requirements.
Technologies: Swift, iOS, Augmented Reality (AR), iOS SceneKit, ARKit, Android, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps
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, Mobile App Development, Mobile Applications, Back-end Development, Mobile Development, Mobile Apps, Server-side, In-app Purchases, Apple Subscriptions
Augmented Reality iOS Developer
2022 - 2022
Trigger
- 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, API Integration, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps, Performance, Memory Management
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, API Integration, Mobile App Development, Mobile Applications, Back-end Development, Mobile Development, Mobile Apps, Server-side, In-app Purchases, Apple Subscriptions, Continuous Deployment
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, Mobile App Development, Mobile Applications, Back-end Development, Mobile Development, Mobile Apps, Server-side, Server-side Programming, In-app Purchases, Apple Subscriptions, Memory Management, Performance
Artificial Intelligence iOS Developer
2021 - 2021
Retinus
- 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, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps, Memory Management
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, API Integration, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps, Performance, Memory Management
Senior iOS Developer
2020 - 2020
CozmicGo
- 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, Mobile App Development, Mobile Applications, Back-end Development, Mobile Development, Mobile Apps, Server-side, In-app Purchases, Apple Subscriptions
Augmented Reality iOS Developer
2020 - 2020
Megaverse
- 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, Mobile App Development, Mobile Applications, Mobile Development, Mobile Apps, Performance, Memory Management
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, API Integration, Apple HealthKit, HealthKit, Mobile Applications, Back-end Development, CSS, HTML, JavaScript, Web Applications, Web Development, Cross-platform App Development, Mobile Development, Mobile Apps, Server-side, Performance, Memory Management
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, App Development, API Integration, Mobile App Development, HealthKit, Mobile Applications, CSS, HTML, JavaScript, Web Applications, Web Development, Cross-platform App Development, Mobile Development, Mobile Apps, Server-side
Experience
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
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 as 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 and 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 and 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 and 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 and it included the following features: handling of a trash folder, favorite files, undo feature, and offline use.
CozmicGO
https://www.cozmicgo.orgA Swift-based app where users could create and participate in real-life events (outings) and 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
https://xrstories.co.uk/introducing-block-an-xr-scenographic-tool/An augmented reality 3D drawing app that allows users to draw shapes using Apple's ARKit; the app enables 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 (AI)
A Swift-based app that leveraged an artificial intelligence (AI) model (TensorFlow) to detect objects captured by the device's rear camera. The app processed the camera feed into raw data for the AI model and then used the model's output to highlight detected objects by displaying bounding boxes around them. This provided a real-time view of the detected objects.
Polinations
https://www.polinations.comAn augmented reality (AR) application that generates a unique 3D flower based on the user's personality test and then presents that flower in AR. Users can see and plant each other's flowers and cross-pollinate them, all in AR.
Leap Second
https://apps.apple.com/us/app/leap-second-everyday-videos/id1021405859A Swift-based app for content creation where it creates a collage of photos/live photos that get merged into a video, and the 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
https://momentgarden.comA 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.
Kidney Health App
A Flutter-based app for monitoring kidney health, where I was in charge of the entire development process, both front end and back end and I used Firebase for the back-end services such as login, register, and user data storage.
CU Degree Show
https://apps.apple.com/gb/app/cu-degree-show/id1568162736A Swift-powered augmented reality (AR) app designed to showcase undergraduate projects from Coventry University. As the lead AR/mobile developer, I spearheaded the end-to-end development of the iOS application. To spatially organize the projects in AR, I engineered a spherical layout algorithm based on the Fibonacci sequence, ensuring a seamless and immersive experience by positioning content around the user in a 360-degree sphere.
XR Stories
https://apps.apple.com/ro/app/xrstories/id6443644079A Swift-powered augmented reality (AR) app designed to showcase R&D projects. As the lead AR/mobile developer, I spearheaded the end-to-end development of the iOS application. To spatially organize the projects in AR, I engineered a spherical layout algorithm based on the Fibonacci sequence, ensuring a seamless and immersive experience by positioning content around the user in a 360-degree sphere.
Milton Storybook
https://apps.apple.com/ro/app/milton-storybook/id1296912385A Swift-based interactive storybook designed for children with a read-along feature. I was the sole developer in charge of both the mobile app and the API. The app relies on intricate resources downloaded from a server to generate and display the book.
OSX App
A Swift-based macOS app that imports, visualizes, and generates assets for a suite of mobile apps. It uses ChatGPT to generate images based on a user prompt. I was in charge of the entire development.
Education
2010 - 2014
Bachelor's Degree in Computer Science
University of Craiova - Craiova, Romania
Certifications
JANUARY 2012 - PRESENT
Cisco CCNA (Cisco Certified Network Associate)
Cisco at the University of Craiova
JUNE 2009 - PRESENT
Certificate in Advanced English
University of Cambridge
Skills
Libraries/APIs
CocoaPods, Apple Subscriptions, iOS Native Libraries, Stripe, HealthKit, TensorFlow, Firebase iOS SDK, Firebase Web SDK
Tools
Xcode, Android Studio, Apple Push Notifications, Firebase Authentication, Jira, Git, Apple HealthKit, ChatGPT, WebView, SourceTree, Sketch, Flinto, Adobe Photoshop, Adobe Experience Design (XD), Figma, Slack
Languages
Swift, Objective-C, Dart, C++, CSS, HTML, JavaScript
Frameworks
iOS SceneKit, iOS SDK, Core ML, ARKit, UIKit, iPhone SDK, SwiftUI, Flutter, Core Data, RealityKit, Metal, TensorFlow Lite, Cocoa
Paradigms
REST, Cross-platform, App Development, Mobile Development, Agile, Mobile App Design, Server-side Programming, Continuous Deployment
Platforms
Twilio, iOS, tvOS, Apple TV, Apple Watch, Android, Apple, Mobile, Firebase, MacOS, WatchOS, Amazon Web Services (AWS)
Industry Expertise
Project Management
Other
Augmented Reality (AR), Geolocation, Video Streaming, Audio Streaming, iPad, Minimum Viable Product (MVP), iOS Camera, iOS Video, iPhone, Artificial Intelligence (AI), Videos, Team Management, APIs, In-app Purchases, Networking, Video Processing, App Store, Subscriptions, AR Interfaces, 3D, tvOS UI, API Integration, Mobile App Development, Mobile Applications, OpenAI, Bluetooth, Cross-platform App Development, Mobile Apps, 3D Art, GPS, Maps, Computer Vision, Images, Performance, Memory Management, Optimization, XMPP, Leadership, Large Language Models (LLMs), Server-side, CI/CD Pipelines, 3D Modeling, Back-end Development, Web Applications, Web Development
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