Diego Ballona, Developer in Belo Horizonte - State of Minas Gerais, Brazil
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Diego Ballona

Verified Expert  in Engineering

Ruby on Rails Developer

Belo Horizonte - State of Minas Gerais, Brazil

Toptal member since April 1, 2014

Expertise
APISystem AdministrationJavaScriptJSONRubyRuby on RailsMySQLSassRedisAgile DevelopmentHTML5LinuxProduct DevelopmentSaaS
Bio

In the past 15+ years, Diego has focused on helping all-sized companies build technology products, mostly in mission-critical environments such as financial services, trust and safety, and customer services. He has deep experience in team leadership, software architecture, systems administration, software engineering, and product development.

Portfolio

Spotify
Engineering Management
Facebook
Engineering Management
PayCertify
CentOS, PostgreSQL, Redis, Laravel, PHP, Ember.js, Ruby, Ruby on Rails (RoR)...

Experience

  • JavaScript - 15 years
  • User Experience (UX) - 12 years
  • Shell - 10 years
  • Ruby on Rails (RoR) - 10 years
  • Ruby - 10 years
  • Engineering Management - 8 years
  • Redis - 8 years
  • HTML5 - 8 years

Availability

Part-time

Preferred Environment

Git, Terminal, OS X

The most amazing...

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

Work Experience

Senior Engineering Manager

2021 - PRESENT
Spotify
  • Wrote and executed a technical strategy that saved the business dozens of millions of dollars.
  • Built a strong team of managers, supporting their growth from senior engineer to manager.
  • Resolved multiple corporate risks that existed with third-party vendor software.
Technologies: Engineering Management

Engineering Manager

2020 - 2021
Facebook
  • Grew the cross-functional org from one to 20 people.
  • Ensured 'Ads that click to WhatsApp' scaled safely from <$1M in ARR to $100M+.
  • Updated a legacy ML detection system in favor of Meta's central system used by Facebook and Instagram. It was particularly challenging given WhatsApp's strict privacy standards, leading to $XX millions in yearly savings for Meta.
Technologies: Engineering Management

CTO

2018 - 2019
PayCertify
  • 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.
  • 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 Management

Engineering Manager

2016 - 2018
PayCertify
  • 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)

Experience

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.

Education

2010 - 2011

Incomplete Degree in Information Systems

Centro Universitário UniBH - Belo Horizonte

2009 - 2010

Incomplete Degree in Management

Centro Universitário FUMEC - Belo Horizonte

Certifications

DECEMBER 2019 - PRESENT

CISSP

(ISC)²

NOVEMBER 2019 - PRESENT

CRISC

ISACA

OCTOBER 2019 - PRESENT

CISM

ISACA

AUGUST 2019 - PRESENT

PCIP

PCI Security Standards Council

Skills

Libraries/APIs

Node.js

Tools

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

Languages

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

Frameworks

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

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

Other

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

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