Publication
Apple Watch in a Nutshell: A Feature Introduction for iOS Developers
https://www.toptal.com/developers/ios/apple-watch-in-a-nutshell
Antonio is currently unavailable
Antonio Bello
Verified Expert in Engineering
iOS Tech Lead and Developer
Chrzanow, Poland
Toptal member since May 6, 2013
Bio
With 27 years of experience, Antonio is a passionate, self-motivated, result-driven, and versatile IT professional specialized in translating business requirements into software solutions, covering the entire software development lifecycle, either autonomously, as part of a team, or as a team leader, using and quickly adapting to any development methodology, programming language, framework, and technology.
Portfolio
Journey Rewards Inc.
iOS, Swift, Strapi, RESTFul APIs, iOS SDK, Xcode, React Native...
Lighten
TypeScript, JavaScript, PostgreSQL, Next.js, Flutter, Android, iOS, React
Elapsus
Back-end, UIKit, OpenGL, Android SDK, Android, MongoDB, Java EE (Jakarta EE)...
Experience
- iOS - 12 years
- JavaScript - 10 years
- Swift - 10 years
- Objective-C - 8 years
- Node.js - 4 years
- SwiftUI - 3 years
- ARKit - 1 year
- Go - 1 year
Work Experience
iOS Developer
2025 - PRESENT
Journey Rewards Inc.
- Collaborated with cross-functional teams, including designers and back-end engineers, to translate product requirements and visual designs into polished, user-facing iOS features.
- Provided ongoing maintenance across multiple platforms (native iOS, Android, and Kotlin Multiplatform shared layer), ensuring consistency and stability across the entire mobile ecosystem.
- Integrated RESTful APIs with a Strapi back end, ensuring seamless data synchronization and robust error handling across the application.
- Contributed to the React Native migration initiative, implementing new features in the codebase while ensuring feature parity with native implementations.
Technologies: iOS, Swift, Strapi, RESTFul APIs, iOS SDK, Xcode, React Native, Kotlin Multiplatform, Android, Kotlin, TypeScript
Senior Full-stack Engineer, Tech/Team Lead
2024 - PRESENT
Lighten
- Managed back-end development with TypeScript, Next.js, and PostgreSQL while handling front-end with React and mobile app maintenance using Flutter.
- Oversaw technical project management, driving clear priorities, efficient workflows, and seamless coordination across product and leadership.
- Mastered quickly new tech stacks such as TypeScript, React, Next.js, and Flutter to build, maintain, and optimize critical systems.
Technologies: TypeScript, JavaScript, PostgreSQL, Next.js, Flutter, Android, iOS, React
Owner, Software Engineer
2004 - PRESENT
Elapsus
- Created desktop-based applications to interface with and gather data from a laser-induced plasma spectrometer (LIPS) and an electronic microscope, perform analysis on input data, and submit results to a remote web service. The LIPS application is used to determine the chemical composition of the observed sample, whereas the microscope application reconstructs an interactive 3D model of the analyzed surface.
- Developed an event organizer to record and report the organizational information related to events, such as races and marathons.
- Implemented a framework to parse RSS and Atom feeds and import articles into a Goss iCM CMS, designed to be easily extensible to other feed types. Also implemented a bulk user import procedure to scan CSV files, find matches between CSV content and CMS fields, check for data errors, and import users into the CMS.
- Developed the course administration/management module for an e-learning system built on top of the Kentico CMS.
- Worked on several projects for a mortgage company to improve internal processing/task automation, many of which were created as proofs of concept and mostly with Google-related technologies.
- Created an App Engine Java application to pull data from an Encompass database (via MS Access and scheduled upload to/synchronization with Google Data Store) and display detailed employee/branch/company statistics, with automatic page rotation and optimization for full screen LCD TVs.
- Created a web-based calendar/scheduler to pull data from an Encompass instance and publish details and totals.
- Developed a web-based application to send SMS messages, manage contacts and group lists, and buy and manage credit.
- Implemented a Windows mobile order entry application, ported from an existing C++ application.
- Re-engineered a costs and sales management application for a large Italian paper mill company/group.
- Developed an online monitor for credit repair software which gathered data from clients and provided real-time statistics.
- Created a database-driven website to search and filter a mortgage database as well as target loan officers.
- Developed a web-based interactive door designer which allowed users to design and order doors.
- Developed a database-driven company website with protected areas for forum discussion and more.
- Created a job board specifically targeted at game designers and developers for the Canadian market.
- Developed an ad banner management system consisting of an administrative interface for publishers and advertisers and a banner engine responsible for banner provisioning.
- Created a website/service for a print, warehousing, and distribution service company which enabled users to order online and track previous/pending orders, and personnel to process orders.
- Commissioned by the Newcastle Youth Council (UK) to develop a web portal with simple-to-use CMS and able-to-send SMS, ringtones, logos and WAP-push messages.
- Developed a Windows Mobile order entry application for resellers/distributors of ice cream/frozen products. After initial development and release of version 1.0, the product evolved by gaining hundreds of new features over its 10 years of existence.
Technologies: Back-end, UIKit, OpenGL, Android SDK, Android, MongoDB, Java EE (Jakarta EE), Agile Software Development, .NET, iOS SDK, Git, C#, SQL, Python, JavaScript, Java, C++, C, Objective-C, Swift
Senior Mobile Developer (Swift)
2024 - 2024
Toptal Client
- Architected a modern iOS foundation and designed a scalable mobile app architecture prioritizing reusability, modularity, and testability, setting the stage for long-term development efficiency.
- Optimized development processes and delivered actionable recommendations to enhance development workflows, QA practices, and release pipelines, driving smoother and more reliable app iterations.
- Contributed to ongoing iOS app maintenance, addressing critical updates and ensuring seamless user experiences.
Technologies: Swift, SwiftUI, iOS
Full-stack Software Engineer
2024 - 2024
Ray Curtis LLC
- Built an interactive front end using React to import, parse, and aggregate large datasets of historical trading data from the back end, enabling efficient data exploration and analysis.
- Designed and implemented multiple data visualization formats, including tabular views, dynamic graphs, and calendar-based visualizations, to deliver clear insights and actionable intelligence for trading strategies.
- Optimized performance by implementing efficient data caching and pagination strategies to reduce the initial load time and ensure smooth user interaction with large datasets.
Technologies: TypeScript, Next.js, MongoDB, React
Senior iOS Engineer
2021 - 2024
Pivot
- Added new features and improved existing ones to help users quit smoking.
- Improved the overall quality of the code and architecture.
- Worked with the rest of the team and provided mentorship to interns.
- Designed a bridge to make legacy UIKit code interoperate with SwiftUI. The goal is to keep legacy code without major refactoring and expose it to SwiftUI-based development and the other way around.
- Designed a package-driven MVVM-C pattern to enforce separation of concerns by embedding features into individual packages and exposing only a simple interface. The goal is to adopt a modular architecture, where each feature is isolated and testable.
Technologies: iOS, Swift, UIKit, SwiftUI
Freelance Software Engineer
2013 - 2021
ByteFactory (www.getvgl.com)
- Performed regular maintenance on the iOS app, implementing new features and fixing bugs.
- Contributed to the development of an in-house JavaScript-based bridging framework to reimplement the service on Android and the web.
- Performed occasional maintenance of the back end using Java, Spring, and MongoDB.
- Implemented end-to-end messaging encryption in the chat section.
Technologies: Back-end, UIKit, Java EE (Jakarta EE), iOS SDK, Git, MongoDB, Spring, JavaScript, Java, Android, iOS, Objective-C
iOS Engineer
2020 - 2020
Swiftlane
- Worked on the iOS app used by people to unlock doors, either in place (via Bluetooth and facial recognition) and remotely.
- Implemented an intercom feature to receive calls from visitors at the access point and remotely unlock to get them in.
- Took care of generic maintenance, bug fixing, improvements, and overall quality.
Technologies: UIKit, Agile Software Development, iOS SDK, Git, Core Bluetooth, CallKit, PushKit, Swift, iOS
Lead Engineer, Software Architect
2019 - 2019
Toptal Client
- Worked on an app to share locations with friends, from its conception, contributing to defining the requirements, designing the architecture, and developing the iOS app and the back end.
- Provided architectural and technical leadership for the mobile development team, coordinating with a remote team and distributing responsibilities.
- Drew together requirements on project needs from various stakeholders and cross-functional team members.
- Learned the Go language while implementing the back end.
Technologies: Back-end, UIKit, Agile Software Development, iOS SDK, Git, PostGIS, PostgreSQL, Firebase, Google Maps, Go, Swift, iOS
Senior iOS Engineer
2018 - 2019
Toptal Client
- Worked on an app to help people quit smoking.
- Provided generic maintenance for the application, ensuring the best performance, quality, and responsiveness.
Technologies: UIKit, Agile Software Development, iOS SDK, Git, Swift, iOS
Senior iOS Engineer
2018 - 2018
Toptal Client
- Joined a team to develop a service for finding and instantly hiring body guards, conceptually similar to Uber.
Technologies: UIKit, iOS SDK, Git, Swift, iOS
Senior iOS Engineer
2017 - 2018
Toptal Client
- Worked on a club finder social app.
- Joined the project to complete the development of an app, to discover clubs around you.
Technologies: UIKit, iOS SDK, Git, Core Location, Mapbox, Swift, iOS
Software Engineer
2017 - 2017
Apps for Gaps (via Toptal)
- Worked on an app to discover stores around you with your favorite brands.
Technologies: Back-end, UIKit, iOS SDK, Git, MapKit, Swift, iOS
Software Engineer, iOS Developer
2017 - 2017
ILF Mobile Apps (www.ilfmobileapps.com, via Toptal)
- Worked on a private messaging app (voice and text) and secure vault for images and videos.
Technologies: Back-end, UIKit, iOS SDK, Git, Messaging, Encryption, VoIP, Swift, iOS
Software Engineer
2017 - 2017
Brave (www.brave.ly, via Toptal)
- Maintained an existing app (not yet launched) for connecting people that need help with people who can volunteer to provide it.
- Fixed bugs on the app.
Technologies: UIKit, iOS SDK, Git, Node.js, iOS
iOS Developer
2017 - 2017
MindTrust Labs (www.mindtrustlabs.com, via Toptal)
- Worked on a medical app to track sensorial and motor activities for child patients.
Technologies: UIKit, iOS SDK, Git, Swift, iOS
Software Engineer
2017 - 2017
Social Scan (via Toptal)
- Maintained the app by adding new features and fixing some problems.
Technologies: UIKit, iOS SDK, Git, iOS, Swift
iOS Software Engineer
2016 - 2016
Contra (www.contra-app.com; via Toptal)
- Contributed to Contra, a social opinions platform.
- Helped improve the app, add new features, and fix bugs.
Technologies: UIKit, iOS SDK, Git, JavaScript, Node.js, Objective-C, iOS
iOS Software Engineer
2016 - 2016
Keepy (www.keepy.me; via Toptal)
- Contributed to Keepy, a kids’ artwork, schoolwork, and mementos organizer.
- Helped improve the app and fix some bugs.
Technologies: UIKit, iOS SDK, Git, MySQL, JavaScript, Node.js, Objective-C, Swift, iOS
iOS Software Engineer
2016 - 2016
Blue Lasso (www.bluelasso.com; via Toptal)
- Contributed to Blue Lasso, an iPad client for a training and advisory service, focusing on projects, people, and planning tools.
- Added new features and fixed bugs.
Technologies: UIKit, iOS SDK, Git, iPad, Swift, iOS
Freelance Software Engineer
2014 - 2016
Vida.watch (www.vida.watch)
- Implemented a task/goal tracking service.
- Worked with beacons to implement basic indoor positioning.
- Created a watchOS app to start/stop trackers, linked to the iOS app.
- Designed and implemented a Node.js back-end, exposing REST APIs.
- Developed the iOS app.
Technologies: Back-end, UIKit, iOS SDK, Git, SQL, Bluetooth Beacons, Objective-C, Swift, Node.js, WatchOS, tvOS, iOS
iOS Software Engineer
2015 - 2015
RAD Fitkey (www.radfitkey.com; via Toptal)
- Contributed to RAD Fitkey, a body measurement app to create a body profile with just three pictures.
- Joined the team for bug fixing and for adding new features.
Technologies: UIKit, iOS SDK, Git, Swift, iOS
iOS Software Engineer
2015 - 2015
Crowdservice (www.crowdserviceinc.com; via Toptal)
- Contributed to Crowdservice, a platform for customers to post tasks where providers can bid and do the task when selected.
- Helped fix bugs and add new features.
Technologies: UIKit, iOS SDK, Git, Objective-C, iOS
Freelance Software Engineer
2015 - 2015
PooledHouse (www.pooledhouse.com; via Toptal)
- Designed the architecture and developed an iOS app for a service to track jobs, tips, and earnings.
Technologies: Back-end, UIKit, iOS SDK, Git, JavaScript, Google Maps, Parse, Swift, iOS
CTO, Software Engineer
2012 - 2015
Ubersimple, LLC (www.ubersimple.com)
- Designed the high-level architecture of a mobile service used to share lists of apps and digital business cards.
- Implemented the server in Node.js, using both JavaScript and CoffeeScript.
- Implemented the native iOS client app, written in Objective-C and Swift.
- Implemented the native Android client app, written in Java.
Technologies: Back-end, UIKit, Android SDK, Android, MongoDB, Agile Software Development, iOS SDK, Git, SQL, JavaScript, Objective-C, Java
Freelance Software Engineer
2014 - 2014
Burnbook (via Toptal)
- Designed the architecture and developed the iOS app for anonymous posting at Mashable (http://mashable.com/2015/03/26/burnbook-app/#IlyrdxGFEkqE).
- Began development in Objective-C, later progressively replaced by Swift for new features.
Technologies: Back-end, UIKit, iOS SDK, Git, SQL, JavaScript, Parse, Swift, Objective-C, iOS
Freelance Software Engineer
2013 - 2013
Rooted
- Created new features and fixed bugs on a previously developed app, whose purpose is to promote a healthy lifestyle.
Technologies: Back-end, UIKit, MongoDB, iOS SDK, Git, JavaScript, Node.js, iOS, Objective-C
Analyst, Lead Developer
2003 - 2003
AG Team S.r.l. (www.agteam.it)
- Redesigned an existing COBOL ERP application in Java/J2EE.
- Performed maintenance on a Windows CE order entry application.
Technologies: Back-end, Java EE (Jakarta EE), .NET, C#, C, SQL, C++, Java
Project Leader, Analyst, Senior Developer
1997 - 2002
Ksolutions S.p.A.
- Created the first and most popular Italian free SMS service (Kataweb FreeSMS).
- Involved in strategic/pilot workforce management projects using mobile technologies (commissioned by the largest Italian mobile operator and railway company).
- Designed and developed applications on a variety of mobile platforms, such as Apple Newton, Palm Pilot, and Windows CE.
- Designed and implemented an SMS engine to target Windows CE platforms, capable of sending and receiving SMS using a GSM card/mobile phone connected to the device.
Technologies: Oracle, Java EE (Jakarta EE), XML, PL/SQL, SQL, Pascal, Java, C, C++
IT Consultant
1996 - 1996
Zappalà S.p.A.
- Designed and implemented a controller for product delivery automation, identifying products by reading bar codes from a conveyor belt, assigning a client/destination basing on an orders database, and routing them accordingly.
Technologies: SQL, C++
Experience
Book: ARKit by Tutorials
https://store.raywenderlich.com/products/arkit-by-tutorialsAs a co-author, I wrote five chapters guiding the reader into developing an ARKit app to create an interactive billboard, to detect and track images and to detect 3D objects.
Book: SwiftUI by Tutorials
https://store.raywenderlich.com/products/swiftui-by-tutorialsAs a co-author, I wrote three chapters showcasing the SwiftUI components to build declarative user interfaces.
Book: iOS 11 by Tutorials
https://store.raywenderlich.com/products/ios-11-by-tutorialsiOS 11 by Tutorials is a tutorial-based book that teaches how to use the new APIs introduced in iOS 11.
I contributed to this book as a technical editor.
I contributed to this book as a technical editor.
Book: watchOS by Tutorials, Second and Third Editions
watchOS by Tutorials is a tutorial-based book that teaches how to make apps for the Apple Watch.
I contributed to this book as a technical reviewer.
I contributed to this book as a technical reviewer.
Author and Tech Editor at RayWenderlich.com
https://www.raywenderlich.com/u/jedenRayWenderlich.com is probably the most used resource for tutorials, articles, and books related to iOS, and more generally the Apple ecosystem.
I write about programming, freelancing, and working remotely.
I write about programming, freelancing, and working remotely.
Music Production
I enjoy composing songs, and everything related to producing, mixing, and mastering.
Linked here is my growing collection of song excerpts on Soundcloud.
Linked here is my growing collection of song excerpts on Soundcloud.
Swift Essentials, Second Edition
A fast-paced guide that provides an overview of Swift programming
I contributed to this book as a technical reviewer.
I contributed to this book as a technical reviewer.
Game Development with Swift
I contributed to this book as a technical reviewer.
2016 Blue Lasso
The Blue Lasso app supports the training and delivery of services provided by Blue Lasso. Clients use the app in support of the training and advisory. The SaaS-based service engages three intuitive tools focusing on projects, people, and planning.
2016 Vida.watch
Task/goal tracking service.
2015 RAD Fitkey
Body measurement app to create a universal body profile with just three pictures.
2014 VGL (iOS)
Social dating app/service, I took care of maintenance and adding new features to the iOS app, as well as contributing to the development of an in-house cross-platform framework used to build the Android and Web clients.
2015 AppPack (iOS)
Application to share and recommend other applications, links, and videos as well as provide a digital business card service.
2015 AppPack (Android)
Application to share and recommend other applications, links, and videos as well as provide a digital business card service.
2016 Keepy
Keepy is a kids’ artwork, schoolwork, and memento organizer.
Provided maintenance, primarily for adding new features, and synchronizing with the Android team to ensure that all features are consistent across platforms.
Provided maintenance, primarily for adding new features, and synchronizing with the Android team to ensure that all features are consistent across platforms.
2016 Contra
Social opinions platform.
I joined the project to improve the service by adding new features and taking care of some issues - entirely in Objective C, a language already superseded by Swift at that time, but still as powerful.
I joined the project to improve the service by adding new features and taking care of some issues - entirely in Objective C, a language already superseded by Swift at that time, but still as powerful.
2016 Crowdservice
Service for customers to post tasks, where providers can bid on and do the task when selected.
2015 Pooled House
Service to track jobs, tips, and earnings.
2015 Ubliette
Fashion browsing and shopping.
I worked on bug fixes and improvements.
I worked on bug fixes and improvements.
2014 Burnbook (via Toptal)
Anonymous posting app, allowing users to post anonymous text and audio messages as well as videos.
http://mashable.com/2015/03/26/burnbook-app/
http://mashable.com/2015/03/26/burnbook-app/
Education
1988 - 2021
Bachelor's Degree in Computer Science
University of Pisa - Pisa, Italy
Skills
Libraries/APIs
Node.js, REST APIs, Google Maps, OpenGL, React
Tools
Git, TestFlight, Xcode, IntelliJ IDEA, Visual Studio, CallKit
Languages
C, Java, C#, SQL, Swift, Objective-C, JavaScript, C++, Go, Python, Pascal, XML, TypeScript, Kotlin
Frameworks
UIKit, SwiftUI, iOS SDK, ARKit, .NET, ASP.NET, Spring, MapKit, Core Location, PushKit, Core Bluetooth, Android SDK, Next.js, Flutter, React Native
Paradigms
Object-oriented Programming (OOP), Mobile Development, Model View ViewModel (MVVM), Agile Software Development, Test-driven Development (TDD), Agile
Platforms
iOS, WatchOS, Java EE (Jakarta EE), Parse, Firebase, Mapbox, Android, tvOS, Oracle
Storage
MySQL, Microsoft SQL Server, MongoDB, PostgreSQL, PL/SQL, PostGIS
Other
Mobile App Development, Native Mobile Apps, Back-end, APIs, User Interface (UI), Architecture, Technical Leadership, Data Modeling, Full-stack, App Store, Bluetooth Beacons, iPad, VoIP, Encryption, Messaging, Computer Science, CI/CD Pipelines, Deployment, Google Play Store, Strapi, RESTFul APIs, Kotlin Multiplatform
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