Diego Ballona, Ruby on Rails Developer in London, United Kingdom
Diego Ballona

Ruby on Rails Developer in London, United Kingdom

Member since April 1, 2014
In the past 10+ years, Diego's focus has been helping companies building technology-related products, mostly in mission-critical environments, such as financial services and eCommerce. He has deep experience in leadership, software architecture, systems administration, software engineering, and product development. He has very recently joined the team as an engineering manager at Spotify.
Diego is now available for hire


  • PayCertify
    CentOS, PostgreSQL, Redis, Laravel, PHP, Ember.js, Ruby, Ruby on Rails (RoR)
  • PayCertify
    CentOS, PostgreSQL, Redis, Laravel, PHP, Ember.js, Ruby, Ruby on Rails (RoR)
  • NDA2
    MongoDB, MySQL, PostgreSQL, CSS3, HTML5, Shell Scripting, AngularJS, Ember.js...



London, United Kingdom



Preferred Environment

Git, Terminal, OS X

The most amazing...

...thing I've created is a JS plugin for detecting real-time payment fraud on merchant checkout pages through publicly available records and proprietary data.


  • CTO

    2018 - 2019
    • Led a team of six managers responsible for 50+ people in engineering, data, design, product, DevOps, security, and quality.
    • Managed CAPEX, OPEX, and all budgeting related to technology efforts.
    • Led quarterly objectives and key results definitions.
    • Actively participated in shaping culture, recruiting, and team building.
    • Implemented policies and procedure guidelines for information security, business continuity, disaster recovery, secure software development, and access control.
    • Led compliance efforts for PCI-DSS Level 1 certification.
    Technologies: CentOS, PostgreSQL, Redis, Laravel, PHP, Ember.js, Ruby, Ruby on Rails (RoR)
  • Engineering Manager

    2016 - 2018
    • Led 4+ teams totaling 20+ people in engineering, data science, design, product, DevOps, and quality.
    • Led the development of technology to prevent credit card fraud through public records, device fingerprinting, geolocation data, network data, persona creation/linking, and social media data.
    • Helped create a model for fraud contexts such as bin attack, chargeback/friendly fraud, and application fraud as well as by generating a fraud propensity score based on hundreds of data sources.
    • Led integrations to 50+ APIs, from modern REST interfaces to legacy ISO 8583-based communication,.
    • Managed and facilitated processes of engineering, design, and product teams while reporting to the CEO.
    Technologies: CentOS, PostgreSQL, Redis, Laravel, PHP, Ember.js, Ruby, Ruby on Rails (RoR)
  • CTO, Partner

    2012 - 2015
    • Actively participated in the strategic decisions of the company.
    • Led 5+ teams totaling 20+ people, composed of engineers and designers both remote and on-site.
    • Guided product decisions, release/milestones, and the roadmap.
    • Managed CAPEX and OPEX for all tech-related projects.
    • Actively participated in pitching for investors, VCs, and clients.
    • Led a partnership with Softlayer Business Catalyst, an IBM company, for an acceleration program.
    Technologies: MongoDB, MySQL, PostgreSQL, CSS3, HTML5, Shell Scripting, AngularJS, Ember.js, Node.js, Ruby on Rails (RoR), Ruby
  • Lead Software Engineer

    2010 - 2012
    • Led the development of a content management system for the largest Christian school network in Latin America.
    • Oversaw website development for 50+ clients.
    • Led engineering/product/design teams totaling 15 people.
    • Led talent recruitment and management.
    • Developed a 30-second video contest tool that had on its first month 1+ million hits and 2,000 video uploads without any paid advertisement.
    • Ran the operations for a web radio that reached 50 thousand people daily on the central food supplier of Belo Horizonte's state, Minas Gerais (CEASAMINAS).
    Technologies: Shell Scripting, JavaScript, CSS3, HTML5, MySQL, PostgreSQL, PHP, Ruby on Rails (RoR)


  • NDA2 Learning Management System

    On NDA2, we built a Learning Management System (LMS), which gave the students the option to learn according to their preferences. We created methodology and technology in which the content offered consumption through slideshows, videos, interactive learning objects, HTML5 games, and other resources which made the user's learning experience highly customized.

  • PayCertify Payment Gateway

    On PayCertify, I had the opportunity to participate both as an individual contributor (engineer) and a manager on creating a payment gateway for cards not present (online transactions) from scratch. We integrated to multiple processors, including TSYS (now Global Payments), FirstData (now Fiserv), AMEX direct channel, and a few specific use-case processors. The whole process included from the concept phase to full certification with a PCI-DSS QSA company as PCI Level 1.


  • Languages

    Sass, CSS3, Ruby, HTML5, XML, SQL, JavaScript, JRuby, Bash Script, PHP, CoffeeScript, Haml
  • Frameworks

    Ruby on Rails (RoR), Selenium, AngularJS, Laravel, Ember.js
  • Tools

    RSpec, Shell, NGINX, Sublime Text, Ansible, Adobe Photoshop, Adobe Illustrator, Terminal, Git
  • Paradigms

    REST, Test-driven Development (TDD), Object-oriented Design (OOD), Class-based OOP, DevOps, Design Patterns, Scrum, Event-driven Programming, Behavior-driven Development (BDD), Asynchronous Programming, Agile Software Development, Kanban
  • Platforms

    Linux RHEL/CentOS, Red Hat Linux, CentOS, MacOS, Amazon Web Services (AWS), Android, iOS, OS X, WordPress
  • Storage

    JSON, Redis, Elasticsearch, Database Modeling, MySQL, NoSQL, MongoDB, Database Performance, PostgreSQL
  • Industry Expertise

  • Other

    System Administration, Product Development, API Design, Engineering Management, Compliance, PCI Compliance, GDPR, User Experience (UX), Information Architecture (IA), Product Management, Sales, Shell Scripting
  • Libraries/APIs



  • Incomplete Degree in Information Systems
    2010 - 2011
    Centro Universitário UniBH - Belo Horizonte
  • Incomplete Degree in Management
    2009 - 2010
    Centro Universitário FUMEC - Belo Horizonte


  • CISM
  • PCIP
    PCI Security Standards Council

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