Néstor Rubén Marsollier

Contact Information

• Email: [email protected]
• LinkedIn: linkedin.com/in/nmarsollier
• GitHub: github.com/nmarsollier
• Phone: +54 261 503 5118
• Address: Villa Nueva, Guaymallén, Mendoza, Argentina

Personal Information

• Languages: Spanish (native), English (advanced)
• Birth Date: 10-15-1976

Education

• Degree: B.S. Computer Systems Engineering
• Institution: UTN Universidad Tecnológica Nacional, Mendoza, Argentina

Professional Summary

Experienced Android and Backend developer with a strong background in teaching and creating tutorials. Skilled in various programming languages and frameworks, with a refocused on Backend development since 2024 and Kotlin since 2012.

Skills

Backend Developer

• Experience: Since 1995
• Experience: Senior backend developer with expertise in monolith, SOA, and microservices architectures, including DDD when supported by the language.
• Technologies: GoLang, Java, Kotlin, Typescript, Javascript
• Frameworks: JSP, EJB 2 and 3, Spring stack, REST applications
• Databases: SQL (MySQL, PostgreSQL, Oracle), NoSQL (MongoDB), Key-Value (Redis)
• Key Skills: High-performance monolith applications, direct access, various ORMs
• Code Samples:
  • Microservices Demo app in Go with Clean Architecture,
  • Go functional programming project,

Android Native Developer

• Experience: Since 2011
• Technologies: Android SDK, Kotlin, Jetpack Compose, Kotlin Multiplatform, Espresso, JUnit4, SonarQube, Jacoco, Apollo (GraphQL), MVI architecture, Coroutines with flows, Dagger/Hilt, Navigation framework, DataDog, Jira, Figma, Confluence, Slack
• Key Skills: Kotlin, Koin, Google Services, GraphQL, REST, Retrofit, Room Database/SQLite, JUnit, Espresso, Jacoco, Hilt, Dagger, Reactive Paradigm, MVVM, MVC, MVI
• Roles: Technical Leader for Mobile at MercadoPago, Eventbrite
• Architect: MercadoPago
• Methodologies: Agile, Scrum, Jira, Figma, Confluence, Slack, Jenkins
• Companies: Dept, PayPal, MercadoPago, Mercadolibre, Eventbrite, Athos
• Code Samples:
  • Fat Measurements in Kotlin with MVI
  • Nasa Pictures in Compose Multiplatform

Teacher

• Institution: UTN (University)
• Courses: Microservices Architecture
• Code Samples: Microservices Architecture

Personal Projects

Professional Experience

AirBnb

Sr Software Developer
Duration: 2024 - Present
Project: Viaduct Open Source

• Working on software refactoring to make Viaduct available Open Source.
• Methodologies: Waterfall.
• Architecture: Open Source Framework.
• Languages: Kotlin - Java.
• Libraries: Apollo Federation.

Dept Argentina

Principal II Android Developer
Duration: 08/2023 - 04/2024
Project: Prismacolor+ Achievements:

• Caught up within 6 months on an iOS project that had started 3 months earlier.

• Full refactor to apply a solid app architecture.

• Led the development of Prismacolor+, a customer acquisition project.

• Oversaw the architecture and development of the Android platform.

• Coordinated with cross-functional teams to ensure seamless integration and delivery of features.

• Applied best practices for code quality, testing, and deployment.

• Mentored junior developers and provided guidance on architectural decisions.

• Methodologies: Agile.

• Architecture: Eventual MVI.

• Languages: Kotlin.

• Libraries: Jetpack Compose, Kotlin MP, EXO Player.

• Design Patterns: MVI, Dependency Injection.

• Tools: Figma, Slack, Azure.

Backend Sr Developer
Duration: 08/2023 - 04/2024
Project: Financial software Achievements:

• Maintain and develop new features in.
• Applied best practices for code quality, testing, and deployment.
• Methodologies: Agile.
• Architecture: Eventual MVI.
• Languages: Golang.
• Libraries: Gin, Postgresql, Gomock.
• Design Patterns: SOLID, Dependency Injection.

PayPal

Sr Android Developer
Duration: 09/2021 - 08/2023
Project: Mastercard Credit Card Benefits Achievements:

• Reach 98% of code coverage.

• Built the Android UI for Mastercard Benefits.

• Created engagement screens, account summary, transaction details, and payment schedules.

• Implemented event-driven architecture using MVI, Coroutines with flows, and Dagger/Hilt for dependency injection.

• Collaborated with cross-functional teams to ensure seamless integration and delivery of features.

• Conducted code reviews and applied best practices for code quality and testing.

• Methodologies: Agile.

• Architecture: Event-driven, Model-View-Intent (MVI).

• Languages: Kotlin.

• Libraries: Android SDK, Espresso, JUnit4, SonarQube, Jacoco, Apollo (GraphQL), Navigation framework, Dagger/Hilt.

• Design Patterns: MVI, Dependency Injection.

• Tools: DataDog, Jira, Figma, Confluence, Slack.

Mercado Pago

Technical Leader
Duration: 05/2020 - 09/2021

Backend

Project: Money In - Money Out Achievements:

• Fully refactor a microservice.

• Designed and developed money in flows (ask for money, get paid, request income).

• Created money out flows (send money, organize contacts, pay).

• Led technical solutions and implemented core functionalities.

• Programmed 2 microservices to enhance system performance.

• Methodologies: Agile.

• Architecture: Microservices, 3 layers of abstraction, MVC.

• Languages: JavaScript, TypeScript, GoLang.

• Libraries: Amazon AWS, EDS, Object Storage, KWS, Apache Kafka.

• Design Patterns: Functional, Clean.

• Tools: Amazon AWS, Apache Kafka, MySQL.

Android

Project: Money In - Money Out Achievements:

• Lead 12 developers.

• Refactor a complex architecture.

• Coach Jr developers up to Sr level.

• Oversaw the architecture and development of the project.

• Designed and developed money in flows (ask for money, get paid, request income).

• Managed a team of 6 junior developers, coordinating the development of 4 modules and 3 libraries.

• Created money out flows (send money, organize contacts, pay).

• Led technical solutions and implemented core functionalities.

• Coached developers on technologies and architectures, ensuring adherence to best practices.

• Methodologies: Agile, Waterfall.

• Architecture: Event-driven, MVC, MVVM.

• Languages: Kotlin.

• Libraries: AndroidX Test, Espresso, Jetpack, OkHttp, Retrofit, ktx extensions, LiveData, Picasso, MockWebServer, PlayServices, Firebase, Gson, Google Maps.

• Design Patterns: Creational, Observers, State, Strategy, Command, Adapter, IoC.

• Tools: Jira, Bugsnag, Google Suite, Zeplin, CircleCI, GitHub, DataDog, Trello, Slack, Kafka.

Eventbrite

Senior Software Engineer II
Duration: 07/2016 - 05/2020
Project: Organizer App Achievements:

• I was the one person Android project against the job done by 12 iOS devs on the other app.

• Fully Refactor the app 2 times to adapt to new patterns. (java to kotlin, kotlin to MVVM reactive architecture)

• Responsible for all architectural and development decisions.

• Refactored the application twice to improve performance, maintainability, and scalability.

• Designed and implemented a fragment-based navigation system using MVC and MVVM architectures.

• Developed features using Java and Kotlin, ensuring high code quality and adherence to best practices.

• Applied event-driven architecture using MVVM, MVC, Repository, DAO (API), and various design patterns including Creational, Observers, State, Strategy, Command, Adapter, and IoC.

• Employed integrations like Jira, Bugsnag, Google Suite, Zeplin, GitHub, Slack, and Jenkins for project management and collaboration.

• Followed Agile and Waterfall methodologies to ensure timely delivery and high-quality software.

• Architecture: Fragment-based navigation, MVC, MVVM, Espresso, Robolectric.

• Languages: Java, Kotlin.

• Libraries: Jetpack, OkHttp, Retrofit, LiveData, Picasso, PlayServices, Firebase, Gson, AndroidX, PayPal Here, JUnit, Room, OrmLite, Analytics, Facebook Login.

• Design Patterns: Event-driven, MVVM, MVC, Repository, DAO (API), Creational, Observers, State, Strategy, Command, Adapter, IoC.

• Tools: Jira, Bugsnag, Google Suite, Zeplin, GitHub, Slack, Jenkins.

• Methodologies: Agile, Waterfall.

Atos Corp

Senior Developer, Architect
Duration: 01/2011 - 05/2014
Project: Redbus

• Acted as Architect and Senior Developer, leading a team of 2 developers.
• Designed and implemented web services to enhance system functionality.
• Utilized technologies including Android, JSP, Java Spring, Oracle, PostgreSQL, NFC, C++, REST.
• Managed and processed large amounts of data efficiently.
• Implemented data synchronization mechanisms to ensure data consistency across the system.
• Developed data consolidation strategies for accurate and reliable data aggregation.
• Ensured consistency control across various system components.
• Created features for card balance management.
• Implemented control over decentralized transaction processing to enhance system reliability.
• Applied object-oriented architecture using domain-driven design (DDD) principles to structure the system effectively.
• Ensured high code quality and adherence to best practices through code reviews.
• Provided mentoring and technical guidance to team members.
• Architecture: Object-oriented, domain-driven design (DDD).
• Languages: Java, JSP, C++.
• Libraries: Spring, NFC, REST.
• Design Patterns: Singleton, Factory, Observer, Strategy.
• Tools: Jira, GitHub, Jenkins.
• Methodologies: Agile, Waterfall.

Belatrix S.A.

Senior Developer
Duration: 03/2010 - 01/2011
Project: StoneRiver

• Acted as Senior Developer for the StoneRiver project.
• Developed and maintained applications using Spring, Mule, Java, and Flex.
• Worked with databases including DB2 and MySQL.
• Followed Agile methodologies and used Rally for project management.
• Methodologies: Agile.
• Architecture: Service-oriented architecture (SOA).
• Languages: Java.
• Libraries: Spring, Mule, Flex.
• Design Patterns: MVC, DAO.
• Tools: Rally, Eclipse, DB2, MySQL.

Senior Developer
Duration: 08/2009 - 03/2010
Project: Talent

• Acted as Senior Developer for the Talent project.
• Developed applications using Spring, Java, JSP, and Hibernate.
• Followed Agile methodologies and used Rally for project management.
• Methodologies: Agile.
• Architecture: Model-View-Controller (MVC).
• Languages: Java, JSP.
• Libraries: Spring, Hibernate.
• Design Patterns: MVC, DAO.
• Tools: Rally, Eclipse, MySQL.

Hewlett Packard Argentina

Specialist Developer
Duration: 02/2008 - 08/2009
Project: SABRE AACoRN System

• Acted as Senior Developer for the SABRE AACoRN System project.
• Developed applications using Java, Swing, EJB2, and Oracle.
• Worked with technologies including SABRE, Web Services, JSP, JaxWS, Axis 2, and Ant.
• Followed CMMI Level 3 standards and used tools like JIRA, Accurev, UML, StarTeam, and SAP.
• Designed and implemented core functionalities for the SABRE AACoRN System, ensuring high performance and reliability.
• Developed complex user interfaces using Swing for a seamless user experience.
• Integrated various web services and ensured smooth communication between different system components.
• Utilized EJB2 for building scalable and transactional business applications.
• Conducted code reviews and enforced best practices to maintain high code quality.
• Collaborated with cross-functional teams to gather requirements and deliver robust solutions.
• Provided technical support and training to team members and end-users.
• Methodologies: Agile.
• Architecture: Service-oriented architecture (SOA).
• Languages: Java, JSP.
• Libraries: Swing, EJB2, JaxWS, Axis 2.
• Design Patterns: MVC, DAO.
• Tools: JIRA, Accurev, UML, StarTeam, SAP.

Suris S.A.

Developer
Duration: 01/2007 - 02/2008
Project: Senectus / Vitae System

• Acted as Developer for the Senectus / Vitae System project.
• Developed applications using Java, Spring, ExtJS, and Hibernate.
• Designed and implemented REST APIs for seamless communication between client and server.
• Worked with SVN for version control, Eclipse as the development environment, and MySQL for database management.
• Ensured robust and scalable application architecture.
• Conducted unit testing and debugging to maintain code quality.
• Collaborated with cross-functional teams to gather requirements and deliver solutions.
• Methodologies: Agile.
• Architecture: RESTful architecture.
• Languages: Java.
• Libraries: Spring, ExtJS, Hibernate.
• Design Patterns: MVC, DAO.
• Tools: SVN, Eclipse, MySQL.

Imaquio S.A.

Technical Leader & Developer
Duration: 01/2002 - 01/2005
Project: Nuebus

• Acted as Architect & Technical Leader for the Nuebus project.
• Developed object-oriented applications with domain-driven design principles.
• Utilized technologies including Java, JSP, and Oracle.
• This was a system to sell long-distance tickets.
• Designed and implemented core functionalities for ticket booking and management.
• Ensured high availability and reliability of the system, which is still in operation.
• Methodologies: Waterfall.
• Architecture: Object-oriented architecture, domain-driven design (DDD).
• Languages: Java, JSP.
• Libraries: Oracle.
• Design Patterns: MVC, DAO.
• Tools: Eclipse, Oracle.

Technical Leader
Duration: 01/2005 - 01/2007
Project: Amadeus Client

• Acted as Technical Leader for the Amadeus Client project.
• Developed applications using EJB 2, Oracle, and Web Services.
• Developed JSP-based user interfaces for seamless user experience.
• This was a system to sell tickets for an airline.
• Designed and implemented core functionalities for ticket booking and management.
• Collaborated with cross-functional teams to integrate various services and APIs.
• Conducted performance tuning and optimization to enhance system efficiency.
• Methodologies: Waterfall.
• Architecture: Service-oriented architecture (SOA).
• Languages: Java, JSP.
• Libraries: EJB 2, Oracle, Web Services.
• Design Patterns: MVC, DAO.
• Tools: Eclipse, Oracle.

CRICYT

Developer, Designer, Analyst
Duration: 05/2006 - 06/2007
Project: Employee assistance control system

• Developed and designed the employee assistance control system.
• Used Java, Swing, and PostgreSQL.
• Implemented an Event Sourcing Database for reliable event tracking.
• Applied real object-oriented architecture with CQRS (Command Query Responsibility Segregation) to separate read and write operations.
• Maintained the event store for capturing application state changes.
• Projections to modify assistance motives in the past, ensuring accurate historical data.
• Provided technical support and training to users.
• Methodologies: Waterfall.
• Architecture: Object-oriented architecture, CQRS.
• Languages: Java.
• Libraries: Swing, PostgreSQL.
• Design Patterns: Event Sourcing, CQRS.
• Tools: Eclipse, PostgreSQL.

Senectus

Developer, Architect
Duration: 01/2000 - 01/2002
Project: Wine traceability system

• Engineered, conceptualized, and evaluated the wine traceability system.
• Leveraged technologies such as Fox Pro.
• Guaranteed system scalability and enhanced performance.
• Partnered with cross-functional teams to collect and refine requirements.
• Performed code inspections and enforced best practices for code integrity.
• Led a team of 3 developers.
• Methodologies: Waterfall.
• Architecture: Object-oriented architecture.
• Languages: Fox Pro.
• Libraries: N/A.
• Design Patterns: MVC, DAO.
• Tools: Fox Pro.

Altamed

Developer, Architect
Duration: 05/1998 - 01/2000
Project: Medicine insurance system

• Developed, designed, and analyzed the medicine insurance system.
• Utilized technologies including Fox Pro.
• Ensured system scalability and performance optimization.
• Collaborated with cross-functional teams to gather and refine requirements.
• Conducted code reviews and implemented best practices for code quality.
• Provided technical support and training to end-users.
• Methodologies: Waterfall.
• Architecture: Object-oriented architecture.
• Languages: Fox Pro.
• Libraries: N/A.
• Design Patterns: MVC, DAO.
• Tools: Fox Pro.

Banco de Prevision Social

Developer
Duration: 08/1995 - 05/1998
Project: Office supply tracking system

• Developed, designed, and analyzed the office supply tracking system.
• Acted as the architect for the refactor to convert the applications to Fox Pro.
• Utilized technologies including Clipper and Fox.
• Ensured system scalability and performance optimization.
• Collaborated with cross-functional teams to gather and refine requirements.
• Conducted code reviews and implemented best practices for code quality.
• Provided technical support and training to end-users.
• Methodologies: Waterfall.
• Architecture: Object-oriented architecture.
• Languages: Clipper, Fox Pro.
• Libraries: N/A.
• Design Patterns: MVC, DAO.
• Tools: Clipper, Fox Pro.

Previous Experience

• Technologies: Clipper, Fox, Fox Pro, Basic, Pascal, Java, JSP, EJB, HTTP, JavaScript, HTML, Oracle, MySQL, PostgreSQL, SQL Server.

  • Clipper: Used for developing database applications.
  • Fox/Fox Pro: Utilized for building data-centric applications with a focus on performance and scalability.
  • Basic: Employed for early-stage programming and scripting tasks.
  • Pascal: Applied for structured programming and algorithm development.
  • Java: Leveraged for building robust, high-performance applications.
  • JSP: Used for creating dynamic web pages and server-side applications.
  • EJB: Utilized for developing scalable, transactional, and multi-tier enterprise applications.
  • HTTP: Applied for web communication and data transfer.
  • JavaScript: Used for client-side scripting and enhancing user interfaces.
  • HTML: Employed for structuring web content.
  • Oracle: Utilized for managing large-scale databases.
  • MySQL: Used for relational database management and data storage.
  • PostgreSQL: Leveraged for advanced database management and complex queries.
  • SQL Server: Applied for enterprise-level database solutions and data warehousing.

• Roles: Various development and architecture roles since 1995.

  • Developer: Responsible for coding, debugging, and implementing software solutions.
  • Designer: Involved in creating software designs and architecture.
  • Analyst: Conducted system analysis and requirement gathering.
  • Architect: Designed and planned software architecture and system integration.
  • Technical Leader: Led development teams and provided technical guidance.
  • Mentor: Provided training and support to junior developers.

UTN Universidad Tecnológica Nacional

Teacher
Duration: 2013 - Present

Course: Microservices Architecture

• Technologies: Java, Angular, Golang, Node.js, TypeScript, Kotlin, RabbitMQ, MongoDB, Redis, Kafka.
• Responsibilities: Developed and taught the Microservices Architecture course.
• Study Plan: Program and Study Plan.
• Code Samples: nmarsollier.
• Duration: 2018 - Present.

Course: Advanced Programming

• Technologies: React, Node.js with TypeScript.
• Responsibilities: Developed and taught the Advanced Programming course.
• Study Plan: Study Plan.
• Code Samples: nmarsollier.
• Duration: 2013 - 2023.

Personal Project Repos

• Nasa Pictures in Kotlin MVI: Nasa - CMP

  • Shows pictures from nasa
  • MVI Jetpack Compose.

• Nasa Pictures in Compose Multi platform: Nasa - CMP

  • Shows pictures from nasa
  • Jetpack Compose Multiplatform.

• Fit Fat Android App: Fit Fat

  • Controls fat and weight in different ways.
  • MVI Jetpack Compose.

• Fit Fat in React Native: Fit Fat React Native

  • Same functionality as the Android app but implemented in React Native.

• Ecommerce Microservices: Ecommerce

  • Ecommerce microservices environment for educational purposes.
  • Includes 5 microservices written in Golang, TypeScript, Java, and Kotlin.

• Golang Tutorial: Golang Tutorial

  • Advanced Golang ideas and techniques.
  • Includes innovative concepts and high-quality code.

• Battery Switch Widget for Android: Battery Switch

  • Switches the battery charger on/off based on battery percentage.
  • Supports Tasmota.

• Volume Widget for Android: Volume Widget

  • A widget to control volume on Android devices.

• My IP Widget for Android: My IP Widget

  • Displays the local IP address in a widget.

• QR Barcode: QR Barcode

  • Generates barcodes from strings for demo purposes.
  • Implemented in Golang.

• Semver Json Store: Semver Json Store

  • Downloads text resources in mobile apps while controlling versions.
  • Implemented in TypeScript/Node.js for educational purposes.

• Document Store: Document Store

  • A simple document store implemented in Golang for educational purposes.

• Card Game in React: Card Game

  • Backend for a card game implemented in React.
  • Designed for educational purposes.

• 4 in Line Game: 4 in Line

  • A simple game for educational purposes.

• Crosswords Board Generator: Crosswords

  • Generates crossword boards.
  • Includes interesting problem-solving techniques.
  • Implemented in Java.

Quick Overview of my most relevant experience

Quick Overview