Gabriel Calero, Developer in Buenos Aires, Argentina
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Gabriel Calero

Verified Expert  in Engineering

Software Developer

Buenos Aires, Argentina

Toptal member since September 15, 2016

Expertise
AndroidJavaGitKotlinMySQLSQLGrailsJenkinsGitHubC++CjQueryJavaScriptCSS
Bio

Along with being a personable and ready-to-help professional, Gabriel is a software engineer and a graduate from NTU in Buenos Aires. He's been working with tech companies for more than 14 years and since 2010, he has performed as a nearshore contractor for US companies. Gabriel also has substantial knowledge in mobile and back-end development, and he has recently achieved the Associate Android Developer certification.

Portfolio

KulpaCloud
Android, Jetpack Compose, Android Jetpack, Firebase Cloud Messaging (FCM)...
Anatomap
Kotlin, Android, PyTorch, Dagger 2
Innodev
Dagger 2, Firebase, Kotlin, Android

Experience

  • Android Studio - 10 years
  • Java - 10 years
  • Bash - 10 years
  • Design Patterns - 10 years
  • HTML5 - 8 years
  • Kotlin - 5 years
  • Gradle - 5 years
  • Dagger 2 - 1 year

Availability

Part-time

Preferred Environment

Java, Bash, Git, Android Studio, Kotlin, Jetpack Compose, Android Architecture Components, Coroutines

The most amazing...

...thing I've coded is an Android SDK to collects data that helps companies to understand their mobile users, their interests, and their needs.

Work Experience

Android Lead Engineer

2022 - PRESENT
KulpaCloud
  • Developed and launched new app features that align with business goals.
  • Diagnosed and resolved crashes, bugs, and performance issues.
  • Migrated legacy code from RxJava2 to Coroutines and from XML views to Jetpack Compose.
  • Kept the code up to date by upgrading to the latest Android SDK and using the most recent version of libraries.
Technologies: Android, Jetpack Compose, Android Jetpack, Firebase Cloud Messaging (FCM), Model View ViewModel (MVVM), Coroutines, Hilt, Unidirectional Data Flow

Senior Android Developer

2019 - 2020
Anatomap
  • Developed an app from scratch for recording injuries sustained as a result of crime.
  • Designed the app's architecture using Android architecture components.
  • Implemented a beautiful UI following high-definition design and UX best practices.
  • Adapted the design from iOS navigation patterns to Android navigation.
Technologies: Kotlin, Android, PyTorch, Dagger 2

Android Developer

2019 - 2019
Innodev
  • Built the in-app wallet feature—among others—in the Walem app for customers using clean architecture principles and Kotlin. This app was recently launched on Google Play in July 2019 and already has 50,000+ downloads.
  • Developed new features for a Swift driver app using clean architecture, e.g., having a screen with a live map showing the zones where drivers are more needed.
  • Provided support for the three apps (customers, drivers, and restaurants) by finding and fixing bugs, including performance issues, notification issues, background status, and list optimization.
Technologies: Dagger 2, Firebase, Kotlin, Android

Android Engineer

2017 - 2019
High Fidelity, Inc.
  • Ported the open-source VR platform HighFidelity (Highfidelity.com) to Android.
  • Developed the UI for the Android app.
  • Developed virtual controls for the in-world view.
  • Ported new features from other desktop platforms to Android.
  • Integrated the Google Daydream SDK to be able to interact with Daydream compatible smartphones using Daydream View (headset) and Controller.
Technologies: CMake, Qt, JavaScript, C++, Google Daydream, Android

Android VR Engineer

2016 - 2017
Futurewei Technologies, Inc.
  • Ported the open-source VR platform High Fidelity (Highfidelity.com) to Android.
  • Ported the graphics backend to Open GL ES 3.2.
  • Adapted the toolchain so it used the proper C++ Clang compiler and GNU STL.
  • Wrote shaders to run on Mali and Adreno GPU.
  • Started integration with Google Daydream platform.
Technologies: CMake, Qt, JavaScript, C++, Google Daydream, Android

Android Fundamentals Course Instructor

2015 - 2016
Ministry of Production and Labour of Argentina
  • Prepared lessons of Android Fundamentals from environment setup to complete app development.
  • Prepared exercises for topics like basic core components, UI, background tasks, storage, networking, geolocation and Maps API.
  • Taught lessons.
  • Coached students in their final group projects.
  • Evaluated and gave feedback to students.
Technologies: Java, Android

Senior Android Developer

2014 - 2016
Intertrust Technologies
  • Participated in the reengineering of Personagraph SDK for Android using TDD.
  • Created the Android architecture using OOP concepts.
  • Developed Android background processes using services and alarm manager.
  • Developed strategies to collect data and send it to the server saving resources usage.
  • Composed unit tests with Junit and Robolectric.
  • Supported a CI configuration with Jenkins and Bitbucket (using Smart Commits).
Technologies: Test-driven Development (TDD), Jenkins, Git, Java, Android

Senior Software Developer

2011 - 2013
Pie Digital, Inc.
  • Supported the Windows Agent for Pie Digital Software.
  • Involved a system tray app and windows service to simplify set-up, management, and remote support of home network and devices.
  • Built Java components with C#.
  • Developed a Windows Installer with InstallShield (InstallScript).
  • Developed a bully algorithm in Java to choose a master PC within the home network.
  • Supported customizations for Telekom (Germany) like i18n.
Technologies: InstallShield, Git, Java, C#

Senior Android Developer

2010 - 2013
iTelo
  • Developed iTelo for Android using MVP pattern.
  • Created a mechanism to search motels on offline devices.
  • Built an offline batch in Java to preprocess images (size, quality, watermark).
  • Developed the Android flow for coupon redemption.
  • Built scripts to deploy on different devices (adb) and run automated tests (Appium).
  • Designed the REST API (JSON).
Technologies: Google Maps API, REST, Java, Android

Senior Development Analyst

2008 - 2010
MercadoLibre, Inc.
  • Built features for the back end of the search engine that supports 2,000 requests/sec using Java.
  • Developed batch jobs to index 60 millions of items and other entities using Java and bash programming.
  • Created offline tools to make content reviewers' jobs easier using Java.
  • Developed a REST API to open the platform to third-party developers using Grails.
Technologies: Git, Grails, Java

Full-stack Web Developer

2007 - 2007
Axxon Solutions
  • Built modular web solutions keeping in mind reusability, maintainability, and quality of the software.
  • Developed back-end and front-end technologies including Java (J2EE) HTML, CSS, and JavaScript.
  • Created an intranet project for Grupo ASSA—a global services company.
  • Devised a catalog and shopping cart solution for Widex—a company that produces and market high-definition headphones.
Technologies: JavaScript, CSS, HTML, Java

Java Developer

2006 - 2007
Intelap
  • Maintained the finance, production, and purchasing modules of the proprietary ERP System.
  • Developed custom reports for different stakeholders and their needs.
  • Refactored and developed a unit test for a financial module.
Technologies: JasperReports, SQL, AWT, Swing, Enterprise Java Beans (EJB), Java

Experience

Personagraph SDK for Android

Personagraph helps companies understand their mobile users, their interests, and their needs. Their goal is to provide actionable user insights to help developers improve mobile user acquisition, engagement, monetization, and personalization efforts.

High Fidelity VR

https://highfidelity.com/
High Fidelity provides a social virtual reality platform for users to create and deploy virtual worlds, and explore and interact together in them.

As an Android engineer, I worked on the Android app which allows users to connect to HiFi through Daydream-compatible devices.

iTelo

https://www.linkedin.com/company/itelo
iTelo is a motel guide app that includes services, pictures, locations, and discount coupons, being the first native mobile app developed for iOS, Android, and Nokia devices, as well as web and web mobile.

MercadoLibre

http://mercadolibre.com/
Mercado Libre, Inc. (MELI) is the leading eCommerce and fintech platform operating primarily in Latin America, offering a comprehensive ecosystem of online commerce, financial services, and logistics solutions. It provides a wide range of products and services, from online marketplace transactions to payment processing (Mercado Pago), lending (Mercado Crédito), and shipping logistics (Mercado Envíos).

Walem

Walem is a platform to order and get food delivered from many restaurants. It provides three different mobile apps for customers, restaurants, and drivers who deliver the orders each one facing different technical challenges.

Injury Capture

Injury Capture is an app that accurately records injuries suffered as a result of violent crime. In using the application, the user helps to provide valuable and robust evidence that the police can then use to swiftly investigate the crime and prosecute those responsible.

The app has a beautiful UI, including custom views like a body map to choose the body part that suffered the injury. It also handles the camera and allows the user to capture pictures and videos.

Education

2004 - 2008

Bachelor's Degree in Information Systems Engineering

National Technological University - Buenos Aires, Argentina

Certifications

JUNE 2019 - JUNE 2022

Associate Android Developer

Google Developers

Skills

Libraries/APIs

AWT, JasperReports, Google Maps API, Android Architecture Components, OpenGL ES, jQuery, PyTorch, OpenGL, RxJava, RxJava 2, RxJava 3

Tools

Eclipse IDE, Android Studio, Git, Jenkins, Gradle, Bitbucket, GitHub, CMake, InstallShield, Android NDK, Android Jetpack, Firebase Cloud Messaging (FCM)

Languages

Java, Kotlin, SQL, HTML, C#, Bash, C++, C, JavaScript, CSS, HTML5, PHP

Paradigms

Object-oriented Programming (OOP), Design Patterns, REST, Model View ViewModel (MVVM), Clean Architecture, Test-driven Development (TDD)

Platforms

Google Daydream, Android, iOS, Docker, Firebase, Software Design Patterns

Frameworks

Grails, Dagger 2, Swing, Qt, Dagger, Android SDK

Storage

MySQL, Redis, DB, Oracle9i, RDBMS, SQLite

Other

Coroutines, Enterprise Java Beans (EJB), Software Design, Software QA, IT Projects, IT Management, Algorithms, Jetpack Compose, SDKs, AlarmManager, User Permissions, Virtual Reality (VR), Shaders, MVVC, Room, Hilt, Unidirectional Data Flow

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