Guillermo Calvo

Guillermo Calvo

Software Developer

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About Me

I’m a Software Developer with wide experience as a Senior Programmer in several platforms: desktop applications, middleware, web apps, e-commerce, smart phones, video games, etc. Any related technology is of interest to me.

I consider myself a versatile and innovative professional; I am capable of carrying out research, analysis, design and development tasks. I can be both a team player and a goal-driven individual, who can work alone and complete deadlines.

I am a dedicated software professional; always looking for new challenges and interesting projects. I love my job and giving 110% every day so I can be proud of what I do.

Latest Projects

exceptions4c Open Source

A C library for error handling through exceptions. Among other functionalities, it lets the developer handle error signals sent by the operative system to the program (such as division by zero). It is portable and supports multi-threading.

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AdMobPlugin For Unity Open Source

An extension for Unity3d which allows you to place Google AdMob banners in your Android games.

View on GitHub

Other Projects

JSON-RPC For Java Open Source

A Java 2 Enterprise Edition library to invoke remote procedures over the JSON-RPC protocol from Java applications. It lets the developer to define which fields of a class must be serialized using annotations.

View on SourceForge

J2ME File System Open Source

A Java 2 Micro Edition library which improves the RMS (Record Management System) for MIDlet developers. With J2MEFS, the data can be stored easily on microdevices, using convenient names and directory trees.

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More projects

Work Experience

Software Engineer - Rakuten (Nov 2017 – Present)

Java 8 Java 11 Spring Framework Play Framework Netty REST APIs Web services Microservices Distributed Architectures Etcd Consul Reactive designs Concurrent Programming Prometheus Grafana Python

Currently working at Rakuten, in RAPID Team, EC Platfor Department. I am one of the main developers of an internal, open-source project which provides a set of Java libraries and other tools to other teams, empowering them to focus on the business logic.

Our team leads a company-wide initiative, whose mission is to accelerate micro-services development through standardization and factorization. We are in charge of building the next generation platform of the company, using state-of-the-art technologies and adopting new concepts and paradigms.

My team is responsible for:

  • Introducing new technologies and frameworks to the company.
  • Providing trainings and best practices to other teams.
  • Designing and providing architectural and technical support on the next generation e-commerce platform system.
  • Implementing distributed backend API systems that support high traffic demand and provide a 24x7 reliable service.
  • Developing the continuous refactors and re-architecture of the system, to comply with the increasing scalability demand and requirements.

Software Engineer - Rakuten (Oct 2016 – Oct 2017)

J2EE Javascript HTML5 CSS3 Glassfish Weblogic Exalogic Shell scripting Maven Jenkins SonarQube TestRail JIRA Bitbucket

Currently working at Rakuten, in Checkout Team of Rakuten Ichiba, Japan’s biggest shopping mall.

Our team is in charge of one of the most critical parts of the e-commerce. Checkout is the process a customer must go through when checking out the items in the cart.

My responsibilities include:

  • Development, system design and implementation of web applications
  • Operations, release managment, system maintenance
  • Investigation of any issues in production servers

Analyst Programmer - GFT (Jan 2015 – Sep 2016)

J2EE Spring MVC JPA RESTful Web Services Apache Tomcat Oracle PL/SQL TeamCity Nexus Maven Angular.js HTML5 CSS3 SASS WebSockets Node.js NPM Bower Grunt

Working at GFT, on the Technology & Innovation Professional Services Unit. My team was responsible for:

  • Identification and adoption of technology trends that may benefit the company
  • Standardization and best practices
  • Development of frameworks to improve efficiency, scalability, robustness and reusability
  • Transfer of technological knowledge to company projects

During the course of my roles, I took part in some projects for a specific German global banking and financial services company.

Senior Programmer - Hewlett-Packard (Jan 2014 – Jan 2015)

J2EE Apache Tomcat Oracle WebLogic Web Services SOAP Oracle Database Siebel CRM

Working at Hewlett-Packard, providing services for some of the largest banking corporations in Spain.

Most of the projects on which I took part, aimed for the integration of CRM systems (based on Siebel) and several other external information systems. This was achieved by developing a layer of middleware based on web services.

Independent game developer - Origame Studio (Jan 2013 – Jan 2014)

Unity3D Game Development C# JavaScript 3D Modeling Android Google Play AdMob

During 2013 I trained as a 3D application developer. I learned Unity3D, an engine with which virtual reality environments can be created for multiple platforms, computers and smartphones.

Kana Memory, an educational app to learn Japanese, is the first Android game I published as an independent game studio.

Senior Programmer - JFactory (Mar 2012 – Aug 2012)

J2EE Tomcat Apache SSL Web Services REST JSON PostgreSQL Dreamweaver HTML5 CSS3

Senior Programmer - IRITEC (Feb 2011 – Feb 2012)

J2EE MySQL SQL Server PHP 5 Zend Nutch Solr Lucene Tomcat Struts Hibernate Spring Web Services SOAP HTML5 CSS3 JavaScript

Senior Programmer - CITIC (Jul 2007 – Sep 2010)

Ambient intelligence RFID Semantic web Ontologies RDF TDT MHP SmartCard J2ME C C++ Qt Python Struts Hibernate JSP J2EE PostgreSQL Web services RPC/JSON SOAP

Freelance Programmer - Neodoo Microsystems (Dec 2006 – Jun 2007)

JBoss Application Server Java Server Faces EJB3 Hibernate JBoss Seam Web Services SOAP

Senior Programmer - Electronic Data Systems (Dec 2005 – Dec 2006)

C C++ J2SE PL/SQL Shell scripting

Programmer - ACK (Mar 2004 – Jul 2004)

Linux Apache MySQL PHP

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