Javier is available for hire
Hire JavierJavier Waitzel
Verified Expert in Engineering
iOS Developer
Buenos Aires, Argentina
Toptal member since April 9, 2014
Bio
Javier is a senior iOS engineer with 10+ years shipping consumer apps end-to-end—SwiftUI front ends, Metal shaders, and Python/GPU AI back ends. He founded a profitable App Store product (18,000+ downloads, $21,000+ in revenue) and delivered client work ranging from official artist apps for Jordin Sparks and Matisyahu to a 3D Gaussian Splatting app launched from scratch. He combines deep native iOS expertise with hands-on generative AI: self-hosted LLMs, ComfyUI pipelines, and autonomous agents.
Portfolio
CSCONNECT Inc.
iOS, Gaussian Splatting, 3D Scanning, Image Processing, ComfyUI
Self-employed
SwiftUI, Python, ComfyUI, Swift, Cloud Computing, GPU Computing
Experience
- iOS - 10 years
- Git - 10 years
- Xcode - 10 years
- UIKit - 10 years
- SwiftUI - 6 years
- Swift - 6 years
- Python - 4 years
- ComfyUI - 2 years
Work Experience
iOS Developer
2025 - PRESENT
CSCONNECT Inc.
- Developed features for CSConnect's production digital menu platform (AI-powered food scanning) as part of the core product team.
- Designed and built SpinSplat, a new 3D Gaussian Splatting app, from zero to App Store launch: a SwiftUI iOS app, a FastAPI and Supabase back end, and a full AI processing pipeline.
- Architected the video-to-3D reconstruction pipeline combining ML models (SAM2, Florence) with industry tools (COLMAP, GLOMAP, Brush) on GPU infrastructure.
Technologies: iOS, Gaussian Splatting, 3D Scanning, Image Processing, ComfyUI
Founder | iOS Engineer
2023 - PRESENT
Self-employed
- Built and launched an AI photo/video editing app, solo, from concept to profitable business: 18,000+ downloads and $21,000+ revenue, currently around $1,700 per month and growing.
- Developed the iOS front end with SwiftUI, UIKit, and custom Metal shaders.
- Engineered the generative AI back end: Python inpainting workflows (ComfyUI/Stable Diffusion) deployed on auto-configured GPU server instances.
- Ran profitable paid user acquisition on TikTok, owning ASO, creatives, and funnel analytics end-to-end.
Technologies: SwiftUI, Python, ComfyUI, Swift, Cloud Computing, GPU Computing
iOS Developer
2025 - 2026
CSCONNECT Inc.
- Added new features and delivered bug fixes in the existing UIKit iOS codebase, helping unify the App Store and TestFlight versions into one maintainable app.
- Improved the Gaussian Splatting generation workflow by applying AI vision models to make results more consistent and reliable.
- Developed an iOS app and a Python back end to generate food Gaussian Splatting models from stationary videos, and tested different approaches for quality and speed.
Technologies: iOS
iOS UI Developer
2015 - 2019
Knxn
- Developed an artist-based app, aggregating content from many sources like YouTube, Twitter, and Instagram.
- Designed and developed features in Objective-C. Migrated to Swift and UIKit and then SwiftUI. Created frameworks for multiple apps to use.
- Implemented a video editor to create content using AVKit and AVFoundation. Worked on the music library integration. Contributed to the creation of gifs, stickers, etc.
Technologies: Objective-C, iOS, Auto Layout, X (formerly Twitter) SDK, YouTube API, Git, REST, HTTPS, AVKit, AVFoundation, SwiftUI, Swift, APIs
iOS Engineer
2015 - 2015
PocketGM
- Created an iOS app to manage all your fantasy teams from different providers in one place.
- Supported the login using different third-party services (Facebook, Twitter, and Google).
- Implemented views with code using Masonry (the Auto Layout framework) supporting all iPhone screen sizes.
- Collaborated with the design team and created reusable views to create a consistent UI.
- Supported continuous integration, code coverage, crash reports, and analytics frameworks.
Technologies: Facebook SDK, iOS, Objective-C, Swift
iOS Engineer
2015 - 2015
Ceevoo (via Toptal)
- Built an app for discovering nearby users using iBeacons (BLE).
- Enhanced "Universal" app experience for iOS using Size Classes.
- Used Core Bluetooth and Core Location simultaneously for advertising and discovering users.
- Implemented Parse integration with a local data store and push notifications.
- Created a framework for discovering users even if the app is closed.
Technologies: Bluetooth Low Energy (LE), Parse, Swift
iOS Engineer
2014 - 2014
uSuit (via Toptal)
- Created a 3D High-Poly model viewer app for iOS (Universal).
- Implemented Dropbox integration.
- Implemented SceneKit and UIKit integration.
- Implemented mesh customization in real-time.
- Created synchronized local storage for offline use.
Technologies: SQLite, Objective-C, Swift
iOS Engineer
2014 - 2014
reTXT (via Toptal)
- Created a text messaging iOS app. Worked with a team of 3 iOS developers.
- Implemented Apache Thrift integration.
- Built a custom SQLite local database.
- Implemented multimedia messages.
- Achieved complex animations using Core Animation and Auto Layout.
- Built an API basis to use in all mobile clients.
Technologies: Core Animation, Apache Thrift, SQLite, Objective-C, iOS
Co-founder | Developer
2010 - 2014
Esqulilax Games
- Migrated several Objective-C/Cocos2D projects to Unity.
- Created an OpenGL-based graphics engine supporting 2D and 3D rendering. Integrated a physics engine (Box2D) using C++. Modified the code to project requirements.
- Designed a custom-level creation tool for the app Climber Brothers.
- Developed several iOS games (Climber Brothers, Battle Rush, Chinchon, and Escoba de 15).
- Created an OBJ (3D models) loader and parser for 3D-mesh rendering.
- Developed the AI for card games featuring a variable level of skill.
- Added support for sharing content on social networks in all of the company's games.
- Incorporated SVG support for curve creation and terrain design. Created a smoothing algorithm using SVG curves and approximation.
- Designed and implemented a PVP (Player versus Player) multiplayer environment for a battle game.
- Developed a server-client framework to display animations simultaneously on different devices.
Technologies: C#, Unity, Objective-C, OpenGL ES, OS X, iOS
Software Engineer
2013 - 2013
iKey SRL
- Developed an iOS and iPad app for final users and admins.
- Developed the Arduino software for interacting with the iOS app and the server.
- Created and deployed the hardware solution for the project using Arduino.
- Integrated two incompatible Arduino shells using a master-slave model.
- Developed several functionalities in the back-end using PHP and SQL.
- Integrated Bluetooth low-energy allowing proximity opening for doors.
- Developed an offline solution and an on-demand synchronization with the server.
Technologies: Bluetooth Low Energy (LE), SQL, Objective-C, PHP, Arduino
iOS Developer
2012 - 2012
Oxean
- Developed the app, "Vale Puerto", for showing company port facilities in Argentina.
- Created the app, "Vale", for displaying company facilities in Argentina.
- Supported image and video display via AVFoundation.
- Designed a custom map interface showing different spots in the VALE facilities.
- Designed a plist-based file for storing and loading map points and information.
- Implemented support for efficient scrolling around the "Vale" app.
Technologies: Objective-C, iOS
iOS Developer
2012 - 2012
Portegno Apps
- Created the "Crazy Hairstyle Studio" app.
- Developed a base framework for editing hairstyles in a realistic hairstyle salon app.
- Added features for camera support, photo editing, and screenshot export to a game.
- Created a Photoshop script for exporting hairstyles and loading them into the app.
- Integrated OpenGL and UIView successfully improving general performance.
- Added support for real-time image editing by rendering images to textures.
- Created an anchor and multi-point manipulation system for displayed objects.
- Built a multi-shading tool for blurring, coloring, and efficient rendering of images.
Technologies: XML, Objective-C, OpenGL ES, iOS
iOS Developer
2011 - 2012
Webetico SNC
- Created a CRM app allowing customers to place orders online and offline.
- Created a multi-language app for a museum displaying information about museum exhibits.
- Integrated image synchronization on demand.
- Developed a framework for synchronizing local data with server data.
- Designed and implemented a custom grid for displaying data.
- Supported communication with an AS400 for an iOS app.
- Supported multithreaded loading of images to display in a catalogue.
- Created a trivia game that allowed prospective customers to enter their contact information.
Technologies: SQL, iOS, Objective-C
Project History
Climber Brothers
An iOS rope physics puzzle game with 4.5/5 stars review.
Free version: https://itunes.apple.com/us/app/climber-brothers-lite/id452800570?l=es&ls=1&mt=8
Free version: https://itunes.apple.com/us/app/climber-brothers-lite/id452800570?l=es&ls=1&mt=8
Battle Rush
An infinite multiplayer PVP runner game.
Crazy Hair Studio
A realistic hairstyle simulator.
Chinchon
A Spanish card game for iOS.
Escoba de 15
A Spanish card game with single and multiplayer features.
iJewels
A jewelry catalogue iPad application for Cielo Venezia.
Award for Esquilax Games
Our company was choosen from 200 indie game companies around the world for the program Chartboost University: Boot Camp and for the GDC (Game Developers Conference).
Education
2009 - 2013
Bachelor's Degree in Software Engineering
Universidad Tecnológica Nacional - Buenos Aires, Argentina
Skills
Libraries/APIs
Parse SDK, Flurry, AVKit, Facebook iOS SDK, AdColony, Dropbox API, X (formerly Twitter) SDK, OpenGL ES, Core Animation, Facebook SDK, SBJson, YouTube API, llama.cpp
Tools
Adobe Photoshop, TestFlight, Xcode, Git, 3ds Max, Adobe Illustrator, Cinema 4D, Microsoft Visual Studio, ComfyUI, Blender, MAMP, Auto Layout
Languages
Swift, Objective-C, Java, Python, C++, C#, XML, PHP, C, SQL
Frameworks
AFNetworking, iOS SDK, Cocoa, Cocoa Touch, SwiftUI, UIKit, Unity, Unity3D, Core Location, Core Bluetooth, Apache Thrift
Paradigms
Object-oriented Programming (OOP), Agile Software Development, XP, Model View Controller (MVC), Continuous Integration (CI), REST
Platforms
iOS, Dropbox, Mapbox, Arduino, OS X, Bluetooth Low Energy (LE), Parse, MacOS, Windows
Storage
SQLite, MySQL
Other
Game Development, Bluetooth, Games, APIs, User Interface (UI), Game Design, HTTPS, AVFoundation, Cloud Computing, GPU Computing, Gaussian Splatting, 3D Scanning, Image Processing, FastAPI
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