John Ernest Guadalupe
Verified Expert in Engineering
Android Developer
Santo Tomas, Calabarzon, Philippines
Toptal member since December 18, 2015
John is a seasoned professional dedicated to delivering impactful, user-centered solutions that align with client goals. With a focus on transforming innovative concepts into market-ready products, he consistently develops high-quality solutions that drive measurable business success.
Portfolio
Experience
Availability
Preferred Environment
Android Studio, Visual Studio, Visual Studio Code (VS Code), Azure, Firebase, Amazon Web Services (AWS), Google Cloud
The most amazing...
...project I've had was leading a 20-person team to develop a super app for food delivery, medicine, and an online wallet.
Work Experience
Associate Manager
EY
- Advised clients on the technical aspects of software development projects, ensuring alignment with business goals and industry best practices.
- Actively involved in go-to-market initiatives, preparing knowledge documents, and performing research presentations to effectively position the company during bidding activities.
- Led multiple mobile projects as the primary developer, fostering collaboration and innovation within cross-functional teams.
- Developed robust software solutions across various projects, leveraging both mobile and web technologies to deliver high-quality applications.
- Built and maintained mobile and web applications as a full-stack developer, addressing bug fixes and implementing new features to enhance user experience.
- Engaged in all project stages, from proof of concept (POC) development and research to ongoing issue management and resolution.
- Improved team productivity by planning development progress, optimizing branching strategies, and implementing CI/CD pipelines for efficient deployment.
Software Architect and Lead Developer
Freelance Work
- Spearheaded all projects, overseeing technical implementations and feature design utilizing Firestore, MySQL, and various other back-end technologies.
- Collaborated with stakeholders and clients throughout the entire project lifecycle, from ideation and research to design, development, launch, and ongoing maintenance.
- Developed applications from scratch, adhering to established methodologies for software development for both corporate and public use.
- Researched and applied various development paradigms as case studies, selecting optimal approaches tailored to specific project niches.
- Leveraged cutting-edge technologies for features like location services, maps, payments, user experience, analytics, and behavioral patterns.
- Led teams, established project deadlines, and collaborated effectively with team members across multiple projects.
- Utilized tools such as Google Sheets, Docs, Slides, Trello, Jira, and DevOps to ensure teams remained organized and on track.
- Maintained direct and timely communication with clients to address concerns and ensure project alignment with their goals.
Hybrid Mobile Insurance Application Developer
Orion180 Insurance Services LLC
- Led the development of a hybrid mobile app using Xamarin, later transitioning to .NET MAUI, enabling company agents to create contracts remotely and enhancing operational efficiency.
- Integrated features from the existing web app by utilizing the same back-end infrastructure, ensuring a seamless user experience and data consistency.
- Developed dynamic forms as the app’s central feature, creating 15 distinct field components that adapt based on insurance products and server responses, optimizing user input.
- Implemented user interface designs using Xamarin Forms and .NET MAUI, customizing controls and views to meet specific platform requirements and enhance usability.
- Expanded app functionality by creating tailored interfaces for customers, marketing personnel, and leadership, providing comprehensive analytics and insights.
- Maintained the application by resolving bugs, implementing necessary adjustments, and incorporating new features in response to evolving business requirements and operational continuity.
Mobile Developer
10 Gears LLC
- Implemented a new server instance with automated publishing of the back-end server from a GitHub Action.
- Managed Android and iOS mobile apps and admin web app code repositories for new feature implementations.
- Led and integrated new database instances for the revamped back end.
Senior Native (Apple and Android) Developer
Imagemakers Inc.
- Used Jira software for tracking tickets and maintaining applications by fixing bugs, adjusting behaviors, and fixing layouts.
- Utilized JavaScript in analyzing and mitigating bugs on the web app.
- Monitored the application performance, adjusting variables and logic as necessary.
Senior Mobile Developer
Navitaire Philippines, Inc. (via NTT Data Philippines)
- Maintained and enhanced existing airline applications for customers, utilizing Xamarin Forms to ensure optimal performance and user satisfaction.
- Diagnosed and fixed bugs across both Android and iOS platforms using C#, ensuring seamless functionality and user experience.
- Developed new features by integrating RESTful services with Xamarin Forms and C#, enhancing the capabilities of customer-facing and operational applications focused on airline operations.
- Collaborated effectively with various departments, including QA, Business Analysis, and stakeholders, to ensure alignment on project goals and timely delivery of high-quality software.
- Created and maintained comprehensive technical documentation for application features, enhancing team knowledge and facilitating onboarding for new developers.
- Conducted performance assessments and optimizations of mobile applications, leading to improved load times and user engagement metrics.
- Engaged with users and stakeholders to gather feedback, translating their needs into actionable development tasks and ensuring the applications meet business requirements.
- Provided guidance and mentorship to junior developers, fostering skill development and promoting best practices in mobile development.
Senior Android Developer
Inovotek Apps, Inc.
- Led the Android team in the implementation of new features to existing projects.
- Maintained existing projects, including handling release and bug monitoring.
- Discussed and implemented the architecture foundations for projects with iOS, web, and design team leaders.
Senior Android Developer
Samsung Mobile R&D Philippines
- Spearheaded the Espresso implementation in projects.
- Maintained existing applications by fixing bugs, adjustments, and aesthetics.
- Implemented new features such as email automation on mobile apps and recognition of content.
Software Developer
KLab Cyscorpions, Inc.
- Developed new features on existing apps. Maintained applications by adding new modules on existing features and/or creating a new module from scratch.
- Resolved app issues by utilizing issue-tracking technologies.
- Code-reviewed pull requests to maintain the quality of code.
- Pioneered the usage and development of a unit testing framework using Robotium.
- Supported, taught, and led junior developers with multiple tasks.
- Helped with improvement and implementation of the current workflow.
Experience
Basketball League Application
Vehicle Dealership Management App
NFTApp
Guapp
I have led the software development team in this project, managing at most 10 people comprised of Android, iOS, and web developers, as well as QA engineers and business analysts. We have used Firebase for the authentication, database, hosting, and analytics. We have also used Stripe for the payments.
I have also led the development of the Android app utilizing Kotlin. I have used the MVVMC architecture using Conductor for the controller and navigation stack, Dagger for dependency injection, Kotlin Coroutines for multi-threading, and Android architecture components such as ViewModel and LiveData.
Tarjemle | Translation Services
I also personally developed the Android application for customers and translators here, wherein they can have documents analyzed and have words automatically counted.
Translators can accept and decline tasks. Both the customers and translators can coordinate with account managers for the tasks and results through the chat module (that we developed). We used Firebase Firestore for the applications' back end.
Pulire | Shoe Cleaning Service
The customer can create an order to upload pictures of a pair of shoes that need servicing and the specific services he wants. After the shop's couriers are notified and accept the pickup request, the app gives them the customer's location. The couriers then collect the items and payments. Once the shoes have arrived at the store, an admin monitors the cleaning process, prompts user updates, and users get notified through push notification. After the service is completed, the shoes will be delivered back to the customer.
PharmacyDirect | A Medicine Delivery System
https://goo.gl/xw44jcI created the client and the delivery personnel applications.
The client application allows users to upload prescriptions and update them about concerning their deliveries, which are automatically managed by the system. It also shows them the current location of the personnel that is delivering the medicine.
For the delivery personnel app, it was designed to give the users notifications when a delivery is assigned to them as well as show the location of the client.
BaryaCard | Financial App
AMPC — https://play.google.com/store/apps/details?id=com.baryacard.ampc&hl=en
Mister Donut — https://play.google.com/store/apps/details?id=com.baryacard.misterdonut&hl=en
InkMyPapers | Assignment Help
Shawer App | eLaw App
Shawer users can purchase in-app currency via the Google Play and the Apple App Store and after purchase can access the available services of various lawyers and services ranging from consultations to legal representation in court.
DURA LEX | Social Italian and European Law Application
Appily | A Journal App with a Personality Analysis
Paloma Forum App
MyWapBlog.com
GetHabal
Education
Bachelor's Degree in Computer Science
Technological University of the Philippines - Manila, Philippines
Skills
Libraries/APIs
Node.js, Android Support Library, Retrofit 2, RxJava, Google API, X (formerly Twitter) SDK, Facebook SDK, React.js, REST API, Stripe Development, Google Maps Development, jQuery, Vue.js
Tools
Bitbucket, SourceTree, Android, Android Jetpack, Expo, WebView, Firebase Authentication, Android, Xcode, Jira, Crashlytics, Visual Studio Development, GitHub
Languages
TypeScript, JavaScript, Kotlin, Java, C#, HTML, CSS, SQL, HTML5, GraphQL, Swift, .NET
Frameworks
React Native, AngularJS, Android SDK, .NET MAUI, Angular, Next.js, Redux, .NET, Espresso, Robotium, ORMLite, Vanilla JS, Bootstrap, iOS, Express.js, Spring Boot
Paradigms
Model View Presenter (MVP), Agile Development, UI Design, UX Development, Testing, Mobile App Design, Clean Code, Object-oriented Programming (OOP), Unit Testing, Spoon Testing
Platforms
Mobile App Design, Firebase, Android, Xamarin, Algolia, Linux, iOS, Windows Development, Eclipse, Azure, Visual Studio Development, AWS
Storage
Firebase Realtime Database, Firestore, JSON, MySQL, Cloud Deployment, SQL Server, PostgreSQL, Database, Google Cloud Development
Other
Technical Leadership, Google Material Design, Google+ Authentication, EventBus, Full-stack, API Integration, Mobile Apps, APIs, Design, Google Play Console, Geolocation, Security, UX Development, UI Development, OCR, App Store Development, Google Play Store, Authentication, React Native Navigation, IT Project Management, IT Projects, Audio, Speech to Text, Text to Speech (TTS), Architecture, Full-stack, Web Application, Biometrics, Cross-platform App Development, Crypto, Image Processing, Artificial Intelligence, Machine Learning, Web Development, Progressive Web Applications (PWAs), CI/CD Pipelines, Xamarin.Forms, Software Architecture, Mobile UI Design, Mobile App Design, Chatbot Development
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