João Dias Barbosa
Verified Expert in Engineering
Mobile Developer
Porto, Portugal
Toptal member since April 4, 2014
João is a passionate iOS and Android developer. With strong attention to detail, he has created many great apps and has delivered many projects for millions of users, both startups and big companies. João has worked extensively on back-end and API integrations. A positive attitude allows him to create on his own and in teams.
Portfolio
Experience
- iOS - 7 years
- Xcode - 7 years
- UIKit - 7 years
- Model View Controller (MVC) - 7 years
- Swift - 6 years
- Model View ViewModel (MVVM) - 5 years
- Combine - 2 years
- SwiftUI - 2 years
Availability
Preferred Environment
Git, Android Studio, Xcode, Android, iOS
The most amazing...
...app I've built was Cashtag, a mobile payments app that allows anyone and everyone to pay their friends in seconds, directly from their account and for free.
Work Experience
SwiftUI iOS Developer
Gratitude Services Inc
- Developed a POC that leveraged the usage of iOS App Clips to provide a better experience for a product order flow for a reorder products application.
- Built a purchase flow composed of a product detail screen and an expandable checkout view using SwiftUI. The product detail screen was fully customizable according to the various product variants available. The product data was available via Shopify API.
- Built an interaction that, by changing the various product options, would update the current gallery image being displayed to match the resultant product variant.
- Built an Instagram-stories-like integration that would display promotional videos for a particular product.
Senior iOS Developer
Fruitful
- Worked on chat features for a financial guidance app through an integration with the Salesforce Chat SDK and MessageKit.
- Refactored the app’s high-level architecture and navigation.
- Built integration with Auth0 to handle authentication.
- Fixed several bugs related to Salesforce chat events and the chat’s working hours and availability.
Senior iOS Developer
- Built from scratch a new module that held a set of fenced features that would enhance the user’s job search by defining an accurate set of criteria.
- Followed the MVVM-C pattern and data handling via GraphQL to complete the development.
- Implemented extensive unit testing (XCTest), UI testing, and end-to-end testing (Calabash).
iOS Developer
Patron Technology
- Built custom integrations for several apps on top of a common codebase.
- Supported integration with Facebook for an event-sharing feature during festivals.
- Fixed bugs on a music player.
- Created a ticket provider that allowed event attendants to check in to certain shows.
- Worked on several custom design changes across various apps.
iOS Developer (Contract)
LVMH
- Built iOS clienteling apps for multiple high-end fashion brands to be used by sales assistants within their boutiques.
- Created an iOS framework that allows the clienteling apps to be built, reusing all the front-end code; Features would be developed once for all customers in a fully native environment.
- Leveraged Payworks iOS framework in a direct purchase flow, which enabled store assistants to handle transactions in the device itself, using a card reader and/or AliPay.
- Built two separate streams of related results for product searches, using Cortexica Vision Systems API, iOS CoreGraphics framework, and IBM Visual Search API.
- Built a standalone iPad app for user signups, intended to enhance the experience for users subscribing to services. Completed with user signature.
Mobile Software Engineer
Glazed Solutions
- Brought many iOS and Android apps from concept to the App Store.
- Created wireframes as well as redesigned and adapted existing apps to newer OS versions.
- Designed and worked on RESTful APIs and back ends for mobile apps using Python.
- Proposed technical and architectural solutions and improvements to existing tech stacks.
- Used Agile methodologies and software management tools to work with teams across the world.
iOS/Android Developer
Small Planet
- Developed for the Wall Art app, in both Android and iOS.
- Created an authentication feature for the Android app.
- Fixed bugs and improved performance on the image display from the respective frames of the available layouts for the iOS app.
- Fixed bugs on filters applied to images for the iOS app.
- Added animations and other UI changes for both Android and iOS apps.
- Added Mixpanel SDK and built a manager to handle the creation of events on the app and track the users' actions.
iOS Developer
Beacinsight
- Developed the data model and the architecture of the app.
- Built an interface for iBeacon communication.
- Developed the logic and architecture of the events that should be generated by the interaction (location/proximity) of the user with the iBeacons.
- Implemented all of the user Interaction/design of the app.
- Implemented different algorithms to enhance the reliability of the iBeacons signal and its interaction with the apps events/logic.
iOS Developer
Keepy (via Toptal)
- Improved a video and audio in-app player.
- Enhanced the app's performance by removing critical overall issues.
- Created a all-new onboarding feature for new users.
- Implemented design changes.
iOS Developer
Rocket Internet
- Worked on the Kaymu iOS app redesign.
- Built dynamic interface components that were reused throughout the app.
- Developed a dynamic process to build custom UI forms according to a schema delivered via an API.
- Created a custom photo cropping tool.
- Built the entire settings logic.
Android Developer, iOS Developer (Contract)
Lapa-App
- Developed an Android and iOS object tracker app that located external devices via Bluetooth.
- Integrated with Parse Android lib, REST API, and cloud functions.
- Implemented push notification and geolocation queries.
- Adapted the app navigation flow and the UX/UI following Google's material design guidelines.
- Implemented the authentication system, allowing both Facebook and email registration.
iOS Developer, Back-end Developer (Contract)
Cashtag
- Developed an iOS peer-to-peer payments app.
- Built the app's design and navigation flows using Auto Layout.
- Integrated with a bank API to receive and forward payments.
- Created and documented a RESTful mobile API using Django REST Framework v2.
- Developed a push notifications service, both on the server and on the iOS side.
Android Developer, Back-end Developer
EatMyDirt
- Developed an Android app where users can create checkpoint-based racing tracks and compete with other users.
- Built the app's UX/UI and navigation flows.
- Implemented the authentication system, allowing both Facebook and email registration.
- Built a non-authenticated flow with some limited functionalities.
- Built the app with Android 4 UI components, maintaining compatibility with 2.3 versions.
iOS Developer and Back-end Developer (Contract)
Treasured
- Developed an iOS journaling app to store pictures and notes and share them with friends and family.
- Created and documented a RESTful mobile API in Django.
- Implemented a permissions system, making each media item available to or editable by specific users or groups of users.
- Implemented the notification and authentication system, allowing both Facebook and email registration.
- Created wireframes, and redesigned UX and navigation flows.
Mobile Engineering Intern
Glazed Solutions
- Worked on a big-data tracking app.
- Refactored an existing native app to a hybrid app that used a WebView to display charts.
- Created an iOS visualization toolkit.
- Developed a data visualization recommender that proposed plot types based on the characteristics of multivariable datasets.
- Built a chart library using some of the most innovative data-visualization frameworks like D3.js.
Mobile Software Engineer
To Better Solutions
- Developed an intelligent task scheduler Android app.
- Created an algorithm that suggested time management tips to the user based on his or her tasks.
- Designed and implemented app UI, following Android design guidelines.
- Defined and implemented a mobile API, model schema, and data handling guidelines for the project.
- Worked on requirements analysis, project management, and client communication.
Experience
XING (New Work)
https://www.xing.com/Throughout this engagement, I built a new module that held a set of fenced features that would enhance the user's job search by defining an accurate set of criteria. The development was done using UIkit and SwiftUI, following the MVVM-C pattern, handling data via GraphQL. It was supported by extensive unit testing (XCTest), UI testing, and end-to-end testing (Calabash).
Seamless Platform
Patron Technology
https://www.greencopper.com/Cashtag
On this engagement, I have built the iOS app and its back end using the Django Rest framework. I was also responsible for implementing push notifications.
Fruitful
In this engagement, I worked on chat features through an integration with the Salesforce Chat SDK and MessageKit. I refactored the app’s high-level architecture and navigation and built its integration with Auth0 to handle authentication. Finally, I fixed several bugs related to Salesforce chat events and the chat’s working hours and availability.
Wall Art
Pleasy Play
Lapa iOS
Integrated with Parse Android lib, REST API, and cloud functions. It used a push notification service and geolocation queries. I was responsible for building the iOS app from the ground up and integrating it with the Parse SDK to connect with cloud functions.
Lapa Android
Integrated with Parse Android lib, REST API, and cloud functions. It used a push notification service and geolocation queries. I was responsible to build the Android app from the ground up and integrate with Parse SDK to connect with cloud functions.
Treasured
Keepy
EatMyDirt
Statz.Me Visualization Framework
Kaymu
Beacinsight
Education
Master's Degree in Computer Science
University of Porto - Porto, Portugal
Certifications
The Complete React Native + Hooks Course
Udemy
Skills
Libraries/APIs
CocoaPods, Alamofire, Parse SDK, Retrofit, Core Animation, D3.js, RxSwift, REST APIs, Shopify API
Tools
Xcode, Aptana, GitHub, Interface Builder, Google Analytics, Crashlytics, Android Studio, Instabug, Auth0, Git, Calabash, Optimizely, JSX
Languages
Objective-C, Java, Swift, Python, JavaScript, GraphQL, SQL, CSS, HTML
Frameworks
iOS SDK, UIKit, XCTest, Combine, SwiftUI, Android SDK, Django REST Framework, Django, Core Data, React Native
Paradigms
Scrum, Agile Software Development, Kanban, Model View ViewModel (MVVM), Model View Controller (MVC), Mobile Development, Refactoring, VIPER Architecture, Agile
Platforms
iOS, Android, Bitrise, Firebase, Salesforce, Contentful, Shopify
Storage
JSON, MySQL, PostgreSQL
Other
GitFlow, Pull Requests, Mobile App Development, Mobile Apps, Mobile UX, Mobile UI, MessageKit, Data Visualization, Push Notifications, Cortexica, User Interface (UI), Animation, SDKs, Bluetooth, User Experience (UX), Communication, Computer Science
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