Cesar is available for hire
Hire CesarCesar David Sosa Perez
Verified Expert in Engineering
Mobile App Developer
Location
Madrid, Spain
Toptal Member Since
September 13, 2022
Cesar is a full-stack software engineer specializing in React Native, Kotlin, and Swift. His broad experience includes developing essential applications in various sectors such as banking, telecommunications, health, and artificial intelligence (AI). Cesar's important area of interest is working with Agile methodologies with CD/CI and the cloud.
Portfolio
Chasing Bacon LLC
Swift, Kotlin, iOS, Android, PHP, Laravel, Vue, Docker, jQuery...
Tata Consultancy Services
React Native, Expo, Ionic, Django, Android, iOS, Node.js...
Electronic IDentification (eID)
Kotlin, Android, iOS, Swift 5, Angular, Java, Spring 4, Stripe Connect...
Experience
Availability
Part-time
Preferred Environment
React, Android, Swift
The most amazing...
...features I've developed are new features for BBVA and Santander Bank financial web/apps.
Work Experience
Swift and Kotlin Developer
2023 - 2023
Chasing Bacon LLC
- Refactored and developed new functionalities in Android native app using Kotlin, MVVM, push notifications, and Firebase Authentication.
- Built and refectored new functionalities in the iOS native app using Swift, SwiftUI, MVVM, push notifications, and Firebase Authentication.
- Developed new functionalities in the REST API using PHP and Laravel, implemented in AWS.
Technologies: Swift, Kotlin, iOS, Android, PHP, Laravel, Vue, Docker, jQuery, Test-driven Development (TDD), React Navigation, Emotion Library, Mobile UX, DevOps
Full-stack Software Engineer
2022 - 2023
Tata Consultancy Services
- Refactored a React Native app to use Redux, Context, and reducers instead of isolated states around the app.
- Developed new Ionic functionalities in TypeScript.
- Led a new feature development, preconfigured dashboards, which integrate applications developed in Ionic, React Native, Django, and BigQuery.
Technologies: React Native, Expo, Ionic, Django, Android, iOS, Node.js, Application State Management, Responsive Web Apps, TypeScript, HTML, AWS Cloud Architecture, Redux, Mobile, Mobile Development, APIs, Front-end Development, Google Cloud Platform (GCP), Full-stack Development, Microservices Architecture, Hybrid Frameworks, Amazon DynamoDB, Stripe, MongoDB, Web Development, Instant Messaging, Full-stack, AI Programming, User Interface (UI), Python, Back-end, SQL, Material UI, Microservices, Amazon RDS, REST APIs, API Gateways, Amazon Simple Queue Service (SQS), Kubernetes, Architecture, Abstraction, Vue, PHP, Docker, jQuery, Test-driven Development (TDD), React Navigation, React Router, Emotion Library, Mobile UX, Cloud, DevOps, Next.js, Heroku, ASP.NET Core
Full-stack Software Engineer
2021 - 2022
Electronic IDentification (eID)
- Developed new Angular, React, and Java functionalities.
- Coordinated using WebRTC protocols for real-time video in the Android, iOS, and JavaScript SDKs.
- Created the pipelines in GitLab for iOS and Android using Gitlab runners and AWS.
- Led new product development, CertID, using NFC reader in Android and iOS using ICAO standard.
Technologies: Kotlin, Android, iOS, Swift 5, Angular, Java, Spring 4, Stripe Connect, REST APIs, HTML, Amazon Web Services (AWS), TestFlight, Mobile, Mobile Development, APIs, Firebase, Google Cloud, Front-end, Front-end Development, Android SDK, SDK Development, SDKs, Full-stack Development, Microservices Architecture, Hybrid Frameworks, Xcode, Swift 4, iOS SDK, Near-field Communication (NFC), Web Development, Early-stage Startups, CSS, TypeScript, Serverless, Full-stack, AI Programming, User Interface (UI), User Experience (UX), Python, Tailwind CSS, SQL, GraphQL, Over-the-top Content (OTT), Android TV, Microservices, Amazon RDS, API Gateways, Amazon Simple Queue Service (SQS), Kubernetes, Terraform, Architecture, Abstraction, Docker, jQuery, Test-driven Development (TDD), React Navigation, Emotion Library, Mobile UX, Cloud, API Integration, ASP.NET Core
Senior Developer
2020 - 2021
Amaris Consulting
- Developed a CE-marked medical app for multiple sclerosis patients to assess neurological functions using novel digital biomarkers focused on movement, balance, dexterity, and vision.
- Applied Scrum methodology to coordinate with international UK, US, and EU teams.
- Created Jenkins Pipelines in cloud for deployments .
Technologies: Android, iOS, REST APIs, Mobile App Development, Mobile Security, Mobile, Mobile Development, APIs, Firebase, Google Cloud, Front-end, Front-end Development, Android SDK, SDK Development, SDKs, Android Studio, Xcode, Stripe Payments, Web Development, TypeScript, Full-stack, User Experience (UX), Tailwind CSS, Web Design, Over-the-top Content (OTT), Android TV, Amazon Simple Queue Service (SQS), Jenkins, Architecture, Docker, jQuery, Heroku, API Integration, ASP.NET Core
Senior Developer
2019 - 2020
AXPE Consulting
- Built the SAN Shareholders and Investors Android and iOS apps for Santander Group, distributed via Google Play and AppStore.
- Developed new features for the "Mi Vuelta" COVID-19 app in React Native.
- Enabled the login integration of the Crisis app in Ionic 4.
Technologies: Android, iOS, JavaScript, TypeScript 3, React Native, Ionic, REST APIs, MySQL, Encryption, User Permissions, TestFlight, Mobile App Development, Mobile Security, Flutter, Mobile, Mobile Development, APIs, Firebase, Google Cloud, Android SDK, SDK Development, Microservices Architecture, Hybrid Frameworks, Android Studio, Stripe Payments, Serverless, Jenkins, Architecture, Scalability, Mobile UX, Swift, API Integration
Technical Consultant
2018 - 2019
Stefanini Group
- Led the mobile development for the BBVA NetCash app QR payments project.
- Managed the SWIFT transfers tracking project for the BBVA NetCash app.
- Solved the incidents reported by the ethical hacking assessment for Android and iOS apps.
Technologies: Android, iOS, .NET Core, User Permissions, Mobile App Development, Mobile Security, Mobile, Mobile Development, APIs, Android SDK, Hybrid Frameworks, Microsoft SQL Server, Objective-C, Web Design, Blazor, Back-end, SQL, Architecture, Scalability
Technical Lead
2016 - 2018
Inca Garcilaso de la Vega University
- Led the development of a tourist application, through machine learning and big data, recognizing monuments of the main cathedrals of Lima, working in real-time using mobile devices' cameras.
- Visited Bucharest, Romania, to receive training in big data and machine learning at the Polytechnica University of Bucharest as part of the UMETECH project.
- Developed and managed the new app for getting familiar with most touristic routes in Lima, Peru, as part of the arrangement with the Lima city council.
Technologies: Android, .NET, C#, SQL, PostgreSQL, C#.NET, MySQL, User Permissions, Mobile, Mobile Development, APIs, Front-end Development, Android SDK, Laravel, Microsoft SQL Server, VBScript, Web Design, Back-end
Full-stack Developer
2014 - 2016
Inca Garcilaso de la Vega University
- Built the university app for more than 40 thousand students.
- Defined the solution architecture using ASP.NET services, SQL, and MySQL databases.
- Developed new features for the students' and teachers' internal enterprise resource planning (ERP) using CakePHP, MySQL, and SQL.
Technologies: PHP, JavaScript, jQuery, ASP.NET, SQL, MySQL, C++, Mobile, APIs, Front-end Development, Laravel, CSS, Visual Basic for Applications (VBA), Active Server Pages (ASP), Blazor
Experience
IMAP Portal
https://imap.windowbook.com/A cloud-based solution code in Angular .NET Core for the back end,
it allows Windowbook clients (mailers) to have a complete view of their undocumented postage statements from USPS (postal service of the US).
I designed and developed the project from scratch and created the CD/CI process in AWS using Bitbucket pipelines, Amazon ECS, Amazon CloudFront (CDN), and Amazon Route 53.
it allows Windowbook clients (mailers) to have a complete view of their undocumented postage statements from USPS (postal service of the US).
I designed and developed the project from scratch and created the CD/CI process in AWS using Bitbucket pipelines, Amazon ECS, Amazon CloudFront (CDN), and Amazon Route 53.
Movistar Smart WiFi
https://play.google.com/store/apps/details?id=com.movistar.co.base&hl=en&gl=USA Kotlin-based app used by more than one million users in Spain, Brazil, and other countries,
This app allows users to manage their Telefonica router in their homes with options like limiting access to specific devices according to timeframes or improving speed for other devices.
I participated in developing a new feature named GamingOn, which allows the user to open ports for specific gaming platforms like Fornite using the mobile phone.
This app allows users to manage their Telefonica router in their homes with options like limiting access to specific devices according to timeframes or improving speed for other devices.
I participated in developing a new feature named GamingOn, which allows the user to open ports for specific gaming platforms like Fornite using the mobile phone.
Financial App for an Important Bank
https://play.google.com/store/apps/details?id=pe.bbvacontinental.netcashA Koltin financial app in which the user could see the global position, accounts, payment services, etc.
I participated in developing two new features: Swift tracking and international tracking of transfers. QR payments enable the business client to start receiving payments using the BBVA Netchash app. I acted as the Android/iOS lead and developer.
I participated in developing two new features: Swift tracking and international tracking of transfers. QR payments enable the business client to start receiving payments using the BBVA Netchash app. I acted as the Android/iOS lead and developer.
Canary - Smart Home Security
https://play.google.com/store/apps/details?id=is.yranac.canary&hl=en&gl=USA Kotlin-based mobile app built on the MVVM Clean architecture, their app improves security in homes around the world using IoT devices like cameras and other devices.
This application lets users see all the cameras installed in their homes in real time and notify them when a person enters their house when the user is out. The application sends the video to the machine learning detection process in Cloud.
This application lets users see all the cameras installed in their homes in real time and notify them when a person enters their house when the user is out. The application sends the video to the machine learning detection process in Cloud.
SAN Shareholders and Investors App
https://play.google.com/store/apps/details?id=es.bancosantander.accionistas&hl=en&gl=USThe app is available in Spanish and English. It offers different functionalities, such as real-time shares prices in all the markets where Santander operates, historical shares info with interactive graphics about evolution and peer comparison, and information about dividend payments and other corporate operations.
Healios+Me
https://apps.apple.com/es/app/healios-me/id1572967523?l=enHealios+Me supports neurology research, helping people diagnosed with multiple sclerosis or related conditions.
Open the app regularly to complete a range of tasks, challenges, and games wherever you are. We use data from your phone's sensors and integration with Apple Health and HealthKit, and analyze it using our cutting-edge algorithms for digital biomarkers.
Open the app regularly to complete a range of tasks, challenges, and games wherever you are. We use data from your phone's sensors and integration with Apple Health and HealthKit, and analyze it using our cutting-edge algorithms for digital biomarkers.
VideoID
https://www.electronicid.eu/en/solutions/videoidSDK and back-end support for the real-time identification onboarding process, working using video streaming technology and machine learning. VideoID works asynchronously, through substantial registration and agent verification, and synchronously through videoconference interviews.
Tourism App
https://play.google.com/store/apps/details?id=pe.uigv.rutaslima&hl=en&gl=USA Kotlin/Java application for tourism, which helps users visit the main routes of Lima, Peru. The application was developed in coordination with the city of Lima.
TOOLS:
• Google Map integration
• MVVM
• Jetpack
TOOLS:
• Google Map integration
• MVVM
• Jetpack
Toptal Node.js Accelerator
The Node.js Accelerator is an exclusive learning program that educates JavaScript/back-end developers in Node.js, Express.js, NestJS, and TypeScript. This is a 2-month program that consists of rigorous learning exercises, live instructor-led sessions by SMEs, hands-on activities, a stringent evaluation process, comprehensive assessments, and an incremental project where participants implement a couple of microservices (REST APIs) using Express.js and NestJs. The incremental project simulates an eCommerce application consisting of two services, i.e., a user service to implement the authentication with user management and a product-catalog service that offers functionalities to manage inventory.
Education
2005 - 2010
Bachelor's Degree in Computer Science
National University of San Marcos - Lima, Peru
Certifications
DECEMBER 2022 - PRESENT
Toptal Node.js Accelerator Graduate
Toptal, LLC
NOVEMBER 2021 - PRESENT
AWS Certified Cloud Practitioner
Amazon Web Services
NOVEMBER 2020 - NOVEMBER 2022
Certified Scrum Master
Scrum Alliance
NOVEMBER 2019 - PRESENT
Associate Android Developer
Google Developers
Skills
Languages
Kotlin, Java, JavaScript, Clean, C#, SQL, PHP, TypeScript, Swift, Swift 4, Objective-C, VBScript, Visual Basic for Applications (VBA), Active Server Pages (ASP), Python, HTML, C#.NET, C++, CSS, GraphQL, Swift 5, TypeScript 3
Frameworks
Angular, React Native, .NET, .NET Core, Dagger 2, Android SDK, Laravel, iOS SDK, Next.js, Blazor, ASP.NET Core, ASP.NET, Redux, Ruby on Rails (RoR), Tailwind CSS, Material UI, Ionic, Django, Express.js, Spring 4, Flutter, .NET 5, NestJS
Libraries/APIs
React, jQuery, Node.js, REST APIs, Retrofit, Alamofire, Vue, React Navigation, React Router, Stripe, Stripe Connect, CocoaPods, Emotion Library
Tools
Jira, Confluence, TestFlight, GitHub, Git, Bitbucket, Android Studio, Xcode, Jenkins, Amazon SageMaker, Terraform, TargetProcess, Trello, Expo, Amazon Elastic Container Service (Amazon ECS), Amazon CloudFront CDN, Docker Compose, Amazon Simple Queue Service (SQS)
Paradigms
Model View ViewModel (MVVM), Clean Architecture, Unit Testing, Mobile Development, Microservices Architecture, Microservices, Object-oriented Programming (OOP), Best Practices, Test-driven Development (TDD), Agile, Scrum, DevOps
Platforms
Android, iOS, Amazon Web Services (AWS), Docker, Mobile, Firebase, Android TV, Software Design Patterns, Kubernetes, AWS Lambda, Heroku, Amazon EC2, Google Cloud Platform (GCP)
Storage
Amazon S3 (AWS S3), Google Cloud, Amazon DynamoDB, Microsoft SQL Server, PostgreSQL, MySQL, MongoDB
Other
User Permissions, Mobile App Development, Mobile Security, UI Testing, Pull Requests, APIs, Front-end Development, SDK Development, SDKs, Full-stack Development, Hybrid Frameworks, Near-field Communication (NFC), Web Development, Early-stage Startups, Serverless, Full-stack, User Interface (UI), User Experience (UX), Back-end, Over-the-top Content (OTT), Amazon RDS, Architecture, Mobile UX, Cloud, Application State Management, Responsive Web Apps, AWS Cloud Architecture, Encryption, Stripe Payments, Instant Messaging, AI Programming, PSD to Swift, Abstraction, Scalability, API Integration, Scrum Master, Autoscaling Groups, Load Balancers, Data Compression, Code Review, CI/CD Pipelines, Front-end, API Gateways
Industry Expertise
Web Design
Collaboration That Works
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