Josip is available for hire
Hire JosipJosip Maric
Verified Expert in Engineering
Swift Developer
Zagreb, Croatia
Toptal member since June 26, 2017
Bio
Josip is a software engineer and iOS developer since 2014. He has spent five years leading 20-person team building World App. He holds a PhD in computer science focused on bioinformatics, has published research on Metagenomic classification, and developed an AI agent for genome assembly.
Portfolio
Flabbergast
iOS, Android, Crypto, Rust, AI Agents
Faculty of Electrical Engineering and Computing, Zagreb
Conda, Python, Algorithms, Bioinformatics, C++
Five
Objective-C, iOS, Swift
Experience
- Swift - 11 years
- iOS - 11 years
- iOS SDK - 11 years
- SwiftUI - 6 years
- C++ - 6 years
- Bioinformatics - 6 years
- Python - 5 years
- Agentic AI - 1 year
Preferred Environment
Xcode, Visual Studio Code (VS Code)
The most amazing...
...thing I've built is an iOS app World App, starting from scratch to 30 million users.
Work Experience
Head of Mobile
2021 - PRESENT
Flabbergast
- Over five years at World, I helped build World App from its first lines of code into a product serving 30 million users, while scaling the development team from zero to 20 developers. https://play.google.com/store/apps/details?id=com.worldcoin.
- I built BioInfo, an AI agent for genome assembly. The project brings AI into complex scientific workflows, connecting computational biology, back-end development, and agent design to support genome assembly.
- I built the MVP for Nolla Health (https://www.nollahealth.com/) from scratch, turning an initial concept into a working application. His development work laid the technical foundation for what has since grown into a global AI-powered health app.
Technologies: iOS, Android, Crypto, Rust, AI Agents
Bioinformatics Engineer
2018 - 2020
Faculty of Electrical Engineering and Computing, Zagreb
- Developed a tool for mapping RNA sequences to the reference genome. It required a lot of C++ coding and algorithm knowledge.
- Created a tool for the classification of metagenomic samples.
- Made a benchmark of metagenomic classifiers. I have used Python, R, and C++.
Technologies: Conda, Python, Algorithms, Bioinformatics, C++
iOS Developer
2014 - 2018
Five
- Created a social network iOS application in Swift where users could ask questions among themselves; used core data and MVVM architecture.
- Developed a Facebook messenger bot that helps users find their desired job position which included back-end support built in Node.js.
- Created numerous iOS applications, with complex UI and UX.
- Created a news iOS application in Objective-C with SDK for ad support which was used in the project.
- Built an iOS application in Swift for helping users in group shopping; the application was built in a reactive paradigm using RxSwift.
- Led the tech development on the last three iOS projects and dealt with all the technical communication with clients.
Technologies: Objective-C, iOS, Swift
Full-stack Developer
2012 - 2013
CROZ
- Worked on both the back-end and front-end of a web application which provided the service of apartment-renting for both landlords and guests.
- Built the back-end of an application mentioned above in Django and Python.
- Worked on the front-end part of the application that was mentioned above using JavaScript, jQuery, CSS, and HTML.
- Acted in a project management role and handled all communication with the client while working on the above project.
- Worked with the MySQL database which was used in the above project.
Technologies: CSS, JavaScript, Python, Django
Full-stack Developer
2012 - 2012
Akcija
- Built a Facebook application where users can compete by solving different quizzes.
- Developed a Facebook application where uses can leave comments on Facebook posts and compete for prizes.
- Built the back-end for the mentioned applications using PHP and MySQL database.
- Developed the front-end of applications using JavaScript, CSS, and HTML.
- Worked a lot with the Facebook API; used it for user authentication and collection of different data.
Technologies: MySQL, JavaScript, PHP
Experience
FLDR | Photo Screenshot Manager
https://apps.apple.com/us/app/fldr-photo-screenshot-manager/id1173652857Built the FLDR app, an app for photo management. The app had various features such as photo import from other apps, map and address usage, complicated photo upload management, and complex UI. Also, I handled the back end of this project, which was done in Node.js.
Moonlite | Storytime Projector
Moonlite is a bedtime reading app that started as a Kickstarter campaign.
· https://www.kickstarter.com/projects/1483155071/moonlite-a-bedtime-story-projector-for-your-mobile)
I worked in a team of three iOS developers. I mostly worked on the UI part of the app, implementing many complicated UI transitions, custom views, and animations. We used Shopify's Mobile-Buy-SDK (the version that uses GraphQL) to integrate purchases.
The app was featured on national television: https://www.facebook.com/TheView/videos/10154983951271524/.
· https://www.kickstarter.com/projects/1483155071/moonlite-a-bedtime-story-projector-for-your-mobile)
I worked in a team of three iOS developers. I mostly worked on the UI part of the app, implementing many complicated UI transitions, custom views, and animations. We used Shopify's Mobile-Buy-SDK (the version that uses GraphQL) to integrate purchases.
The app was featured on national television: https://www.facebook.com/TheView/videos/10154983951271524/.
Nielsen | iOS Video Player Plugins
I have worked on a product developed by Nielsen Holdings PLC, a global information, data, and measurement company. I developed several iOS audio player plugins which can be used by iOS developers to integrate Nielsen SDK into their iOS application.
Working on these plugins, I have gained experience with several iOS video players. Also, I have worked with QA team based in India and a management team in the US and have gained experience working with a big company. All of the communication was handled by me, without a project manager.
· https://engineeringportal.nielsen.com/docs/JW_Player_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/Brightcove_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/thePlatform_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/AVPlayer_Plugin_iOS
Working on these plugins, I have gained experience with several iOS video players. Also, I have worked with QA team based in India and a management team in the US and have gained experience working with a big company. All of the communication was handled by me, without a project manager.
· https://engineeringportal.nielsen.com/docs/JW_Player_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/Brightcove_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/thePlatform_Plugin_iOS
· https://engineeringportal.nielsen.com/docs/AVPlayer_Plugin_iOS
Volumes | Turn Up Your Audiobook
Volumes is an audiobook application from the largest general-interest paperback publisher in the world Penguin Random House. I've worked on this application alone, continuing work that was done by their previous developer. I added a podcast section, worked with Parse as a back-end service and worked with the streaming and audio part of the app.
I worked on this application without project manager handling all the communication with the client by myself.
I worked on this application without project manager handling all the communication with the client by myself.
Planted | Find Jobs You’ll Love
Planted is an application that connects users who seek employment with employers. I built this application from scratch with one colleague. I built some interesting UI solutions and also worked remotely with backend team based in the USA. I was also in charge of communication with the client.
Headliner, an App for Stock News
Built an iOS app from scratch in Swift that delivers the latest stock market news, with push notifications for quick updates and deep linking to take users directly to related articles within the app.
World App
https://world.org/world-moneyOver five years at World, I helped build World App from its first lines of code into a product serving 30 million users, while scaling the development team from zero to 20 developers. https://play.google.com/store/apps/details?id=com.worldcoin.
Education
2018 - 2026
Ph.D. Degree in Computer Science
Faculty of Electrical Engineering and Computing - Zagreb
2009 - 2014
Master's Degree in Computer Engineering
University of Zagreb, Faculty of Electrical Engineering - Zagreb, Croatia
Skills
Libraries/APIs
Facebook SDK, RxSwift, Node.js
Tools
Xcode, Git, SourceTree, Zeplin, Jira, Bitbucket, Eclipse IDE, Sublime Text
Languages
Python, Java, Objective-C, Swift, C++, SQL, CSS, JavaScript, C#, Haskell, PHP, Rust
Frameworks
iOS SDK, SwiftUI, .NET, Django
Platforms
iOS, Firebase, Amazon Web Services (AWS), Visual Studio Code (VS Code), Android
Industry Expertise
Bioinformatics
Paradigms
Model View ViewModel (MVVM), Functional Programming, Object-oriented Programming (OOP)
Storage
MySQL
Other
Scraping, Web Scraping, AVFoundation, Algorithms, Conda, Computer Science, Computer Engineering, Tools, Artificial Intelligence (AI), Machine Learning, Data Science, Crypto, AI Agents, Agentic AI
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