José Maldonado, Software Developer in Buenos Aires, Argentina
José Maldonado

Software Developer in Buenos Aires, Argentina

Member since September 29, 2015
José is a skilled software developer with a computer engineering degree and experience in web development, mobile apps, and bug fixing. He enjoys learning new technologies, contributing to open source projects, and working on interesting and challenging projects.
José is now available for hire


  • Critical Start
    Git, Docker, Python, Flutter, Dart, Express.js, Node.js, React Native...
  • Toptal Clients
    HTML, JavaScript, CSS, Progressive Web Applications (PWA), Games,
  • Termtegrity
    Git, Docker, Python, Grunt, React Native, AngularJS, JavaScript, Sass, CSS



Buenos Aires, Argentina



Preferred Environment

Windows, Git, Sublime Text

The most amazing... I've developed is an immigration control system that was instrumental in uncovering a network of migrant traffickers in Senegal.


  • Software Engineering Manager

    2018 - PRESENT
    Critical Start
    • Developed and maintained a web application for managing incident security alerts.
    • Built and maintained a mobile application for iOS and Android for managing security products.
    • Supported users with issues on both the web and mobile applications.
    • Created an application for managing and running Docker containers.
    • Led a team of UX, front-end, and mobile developers.
    • Implemented a design system to standardize the look and feel of the web applications.
    • Applied data visualization solutions using the D3.js framework.
    • Implemented a Chrome extension for adding new methods of contextual search.
    Technologies: Git, Docker, Python, Flutter, Dart, Express.js, Node.js, React Native, AngularJS, JavaScript, Vue, jQuery, CSS, HTML5, Android, Progressive Web Applications (PWA), Django, Sass, Elasticsearch, Bootstrap, Amazon Web Services (AWS), UX Design, D3.js, Unit Testing, Chrome Extensions, Svelte
  • Full-stack Developer

    2015 - PRESENT
    Toptal Clients
    • Implemented single-page applications (SPA) that consume REST APIs.
    • Handled the implementation of a real-time server using WebSockets to host multiplayer games.
    • Applied implementation of integration layers between applications and third-party services.
    • Maintained and implemented plugins for the content management system (CMS).
    • Integrated a Chrome Extension with JavaScript and React for web scraping.
    • Updated a REST API developed with Python and Django to add new endpoints.
    • Added new functionalities and fixed bugs to HTML5-based games.
    • Implemented and improved UI themes for the eCommerce site.
    • Converted PSD template images into interactive HTML web pages.
    Technologies: HTML, JavaScript, CSS, Progressive Web Applications (PWA), Games,, Cordova, Node.js, WebSockets, AngularJS, jQuery, Sass, eCommerce, Google BigQuery, Elasticsearch, Django, Python, React, MobX, Chrome Extensions, Unit Testing, Angular, Sails.js, Express.js
  • Front-end Developer

    2017 - 2019
    • Transformed the existing web application into a single-page application.
    • Implemented a mobile app for Android and iOS using React Native.
    • Converted wireframe images into interactive HTML web pages.
    Technologies: Git, Docker, Python, Grunt, React Native, AngularJS, JavaScript, Sass, CSS
  • Front-end Developer

    2017 - 2018
    Advanced Threat Analytics (acquired by Critical Start)
    • Developed and maintained the main site, implemented new features, and detected and fixed bugs.
    • Created a mobile application for iOS and Android using React Native.
    • Integrated external services into the main site and the mobile app.
    • Supported users with issues on the leading site and deployed fixes to production.
    Technologies: Git, Docker, Python, Grunt, React Native, React, AngularJS, JavaScript, Sass, CSS
  • Lead Developer

    2011 - 2017
    • Developed and maintained IICS, an integrated immigration control system currently used at several international airports from West Africa.
    • Created an HTML5 application for employee supervision.
    • Integrated the FIND service from INTERPOL at the Ivory Coast and Senegal airports.
    • Designed and implemented software for the management and printing of residence and work permits for the government of Sierra Leone.
    • Managed teams of up to six people using Agile methodologies.
    Technologies: Git, Less, CSS, HTML5, Node.js, React, AngularJS, jQuery, JavaScript, PostgreSQL, MySQL, Microsoft SQL Server, .NET, C#, SQL, SQLite
  • Full-stack Developer

    2010 - 2011
    • Designed and implemented a system for managing purchase and work orders for Romipack.
    • Implemented and designed a web application for managing purchase orders for Delicity.
    • Handled the implementation of a human resources management tool for AON.
    • Developed a reservation management app for Rojo Tango.
    Technologies: CodeIgniter, PHP, Android, jQuery, JavaScript, CSS, HTML, PostgreSQL, MySQL, Java, SQL
  • IT Intern

    2009 - 2009
    Institute of High Voltage and Energy Transmission
    • Developed an application for managing experiments and maintaining the institute's website.
    • Modernized and maintained the laboratory's website.
    • Migrated a database with data about experiments from Excel to MySQL.
    Technologies: JavaScript, CSS, HTML, MySQL, Java, SQL


  • MobileSOC

    A mobile app for Android and iOS that allows faster deployment and containment. The app provides a mobile-first approach to analyst communication, alert investigation, and response beyond a simple ticketing app, which increases the efficiency of SOC analysts by reducing the number of security events that require investigation.

  • Threat Analytics Search

    A Chrome extension for security analysts, malware hunters, and incident responders, enabling the use of the context menu (right-click) in Chrome to conduct single or group searches for the selected text. The most useful scenarios are when you need to search a file hash, IP address, or domain across multiple websites at once.

  • Integrated Immigration Control System (IICS)

    Implemented an immigration control system currently used in several airports in West Africa, which allows for the capture of wanted criminals, detection of tax evaders, and discovery of suspicious travel patterns.

  • SimCo60

    Implemented a scientific simulation tool for estimating radiation exposure levels, developed for the Semi-Industrial Irradiation Plant (PISI) at the Ezeiza Atomic Center, a facility that provides services of ionizing radiation exposure for sterilization of medical equipment, irradiation of food, and decontamination of cosmetics.

  • Patrulla Tu Planeta

    Translation, from English to Spanish, of "police your planet," a science fiction novel about a journalist deported to Mars, initially published in 1953 and written by Lester del Rey, an American science fiction author and editor.

  • Best Graduates in Engineering Careers Award

    An award was granted in 2010 by the National Academy of Engineering to the best engineers who graduated from an Argentinian university in the year 2009, in recognition for their dedication to excellence.

  • The Art of War Applied To Software Development (Publication)
    The Art of War is an ancient military treatise, but despite its age, the text is still included in the syllabus at many military schools. Sun Tzu’s principles and teachings also have practical applications in politics, business, sports, and, believe it or not, software development. In fact, you might just be applying some of these principles in your daily routine, without even knowing. In this post, Toptal Freelance Software Engineer Jose F. Maldonado explains why many of these ancient teachings still matter, and what you can do to make them work for you and your team.
  • Toptal Mentor
    José is a mentor in the Toptal Global Mentor’s Program. This program is a partnership between Toptal and General Assembly to provide high quality mentorship for students from minority and low income backgrounds who are looking to begin their careers as professional software engineers. José shows commitment to diversity in tech by mentoring a General Assembly student every week for a year, covering everything from coding tips and tricks to advice on making it in the industry.


  • Languages

    HTML, CSS, Java, JavaScript, C#, Sass, SQL, PHP, Python, Dart, Less
  • Frameworks

    Bootstrap, AngularJS, .NET, Angular, React Native, CodeIgniter, Sails.js, Flutter, Svelte, Express.js, Django,
  • Libraries/APIs

    jQuery, Node.js, Vue, React, D3.js, MobX
  • Tools

    Git, Grunt
  • Storage

    PostgreSQL, MySQL, SQLite, Microsoft SQL Server, Elasticsearch
  • Other

    Software Development, Software Engineering, Cordova, Progressive Web Applications (PWA), Open Source, Chrome Extensions, WebSockets, IoT Security, UX Research, Games, eCommerce, Google BigQuery, English-Spanish Translation, Apps
  • Paradigms

    Unit Testing, UX Design
  • Platforms

    Android, Docker, Amazon Web Services (AWS)


  • Certificate in Software Engineering
    2009 - 2009
    University of Technology of Belfort-Montbéliard - France
  • Engineer's Degree (Summa Cum Laude) in Computer Sciences
    2004 - 2009
    National University of Tucumán - Argentina


  • UX Design Certificate
  • Data Science MicroMaster
    APRIL 2020 - PRESENT
    UC San Diego

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