Joshua Ballanco, Developer in Miami, FL, United States

Joshua Ballanco

Ruby on Rails Developer

Miami, FL, United States
Toptal Member Since
January 14, 2014

Joshua is an architect, engineer, and scientist with experience building large-scale systems dealing with everything from massive amounts of video data to heavy web traffic. He also has experience breaking monoliths into scalable microservice architectures and going the other way 'round. He's worked for Apple and AOL and has also led a group of 50+ consultants as their chief scientist.

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CoreValue Holdings, LLC
Ruby, JavaScript, Ruby on Rails (RoR), PostgreSQL, CoffeeScript, Angular...
Digital Swiss Gold (USA) LLC
Java, SQL, API Hooking, React, API Integration, A/B Testing, Accounting Software
Glencoe Software
Django, Python, Hibernate, Spring, Java


Miami, FL, United States



Preferred Environment

Amazon Web Services (AWS), Docker, Heroku, Visual Studio Code (VS Code), Git, Emacs, Vim Text Editor, Linux, OS X, Tailwind CSS

The most amazing...

...bug I've fixed required taking a system that couldn't even handle two machines and scaling it to over twenty in less than four weeks before shipping a new OS.

Work Experience

2020 - 2021

Expert Full-stack Developer

CoreValue Holdings, LLC
  • Updated a legacy application from Rails 3.0 to Rails 6.0.
  • Refactored survey and data input system to facilitate further customization and other new feature development.
  • Expanded the core product to serve new industries and an expanded customer base.
Technologies: Ruby, JavaScript, Ruby on Rails (RoR), PostgreSQL, CoffeeScript, Angular, Heroku, Accounting Software, jQuery, Stimulus
2020 - 2021

Full-stack, Back-end Developer

Digital Swiss Gold (USA) LLC
  • Enhanced a mobile app prototype in preparation for a wide-scale production launch.
  • Refactored an order-processing back-end to enable distributed deployment.
  • Implemented various analytics tracking capabilities to monitor customer engagement.
Technologies: Java, SQL, API Hooking, React, API Integration, A/B Testing, Accounting Software
2013 - 2019

Senior Software Developer

Glencoe Software
  • Supported the migration of a Spring/Hibernate system from PostgreSQL to Oracle.
  • Designed and implemented a distributed messaging system to connect various components in a data collection pipeline.
  • Created JNI-based bindings for a JPEG XR decoder written in C.
  • Wrote a library to coordinate the submission of jobs to an HPC grid facility from a Python/Django web app.
  • Implemented a custom Window's URL handler to enable launching local applications against data on a central server from within a browser window.
Technologies: Django, Python, Hibernate, Spring, Java
2017 - 2018

Senior Architect

Simple Global, Inc.
  • Led company-wide planning for a transition from a single monolith to microservice-based architecture.
  • Guided decision making around the selection of technology stack, deployment infrastructure, and the continuous delivery pipeline.
  • Designed and implemented OpenAPI specification, driven API documentation, and automated testing.
  • Assisted with metrics collection and ETL workflow for accounting data.
Technologies: DevOps, Code Architecture, API Architecture, API Design, Spring, Java, Node.js, Express.js, Architecture
2014 - 2018

Senior Software Engineer

Hendrick Automotive
  • Designed and deployed AWS CodeDeploy/CF-based architecture for deploying internal back-office apps.
  • Developed APIs to support business analytics.
  • Migrated an existing code base from Datomic to PostgreSQL.
  • Developed a Clojure-based web application to manage employee performance and goal setting.
  • Developed middleware services to connect an array of third-party back-office systems.
Technologies: Amazon Web Services (AWS), React, Ruby on Rails (RoR), Datomic, Clojure
2014 - 2014

Software Engineer — RoR

  • Extended a CMS-like system to host FAQ content.
  • Updated HTML and CSS for various static pages.
  • Implemented a dynamically resizing button menu.
  • Updated responsive design elements for mobile browsers.
  • Fixed a variety of minor bugs in a legacy Rails codebase.
Technologies: Clojure, CSS, JavaScript, Ruby on Rails (RoR), Product Management
2011 - 2013

Chief Scientist

Burnside Digital
  • Developed client infrastructures using various components of Amazon Web Services.
  • Worked with teams at RedHat to build solutions on the JVM and JBoss platforms.
  • Developed components of an SOA infrastructure that supports a variety of client projects, including the CityEats platform we developed for Scripps Network Interactive.
  • Presented technical solutions at software conferences around the world.
  • Helped introduce and develop new technologies with our team of 20+ software engineers.
Technologies: Chef, Java, Clojure, Objective-C, JavaScript, Ruby on Rails (RoR), Agile
2011 - 2011

Support Engineer

  • Fixed bugs reported on the main app.
  • Responded to support requests from Exceptional customers.
  • Developed integration between Exceptional and Pivotal Tracker.
  • Monitored servers for service interruptions and helped to diagnose, troubleshoot, and fix emerging issues.
  • Assisted with transitioning the technology stack to new owners.
Technologies: AWS Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Redis, Memcached, JavaScript, Ruby on Rails (RoR)
2010 - 2011

Back-end Software Engineer

  • Migrated the primary CMS application from Ruby Enterprise Edition to Ruby 1.9.2.
  • Optimized database performance and helped maintain consistent page load times across an order of magnitude increase in traffic.
  • Scaled the platform from less than 100 locations to over 800 in less than three months.
  • Designed a service-oriented architecture overhaul of the entire publishing platform.
  • Participated in a company-wide effort to embrace open source and encourage employees from all departments to participate in the open-source community.
  • Implemented A/B testing in consultation with marketing and editorial to gather feedback on headlines and advertising layouts.
Technologies: JavaScript, Redis, MongoDB, MySQL, Ruby on Rails (RoR)
2006 - 2010

Server Software Engineer

  • Developed a Grand Central Dispatch-based web server for MacRuby called ControlTower.
  • Upgraded the product for two major Rails revisions and one Ruby version.
  • Managed the QA process for the team’s deliverables.
  • Implemented a web interface, including a near real-time video preview system built with only HTML, CSS, and JavaScript.
  • Improved server and database performance from less-than-acceptable to ready-to-release.
Technologies: SANs, Quartz Composer, QuickTime, C, Objective-C, Ruby on Rails (RoR), Xcode Server



CityEats was a platform for customers to make reservations at popular restaurants, and also for restaurants to manage availability and offer special reservations for promotional events. With Burnside Digital, I assisted in maintenance and the development of new features. I also led a team that re-implemented the integration between the customer-facing site and the reservation management back-end utilized by restaurants using a service-oriented architecture.

ControlTower is an HTTP application server for MacRuby. As a member of the OS X Server team at Apple, I developed ControlTower to meet the needs of a larger project, as there were no existing application servers at the time that worked with MacRuby and met all of the project requirements.

Evolver is a "toy simulation" of an evolutionary system that I implemented as part of my doctoral thesis research in the field of evolutionary biology. Utilizing Ruby, it allows for all of the important parameters of the simulation to be specified via configuration file, while still running fast enough to complete simulations in a reasonable amount of time.

Y-Combinator for Objective-C
In the process of studying both Objective-C and the various fixed-point combinators from the lambda calculus, I conceived of a way to utilize Objective-C's blocks to implement the Y-combinator. This is more of a fun, exploratory project than something intended for production use (though there's no reason it shouldn't work in a production system).
Image of Learning Swift Programming: Is it Ready for Prime Time? publication

Learning Swift Programming: Is it Ready for Prime Time?



HTML, HTML5, Java, Python, Ruby, JavaScript, C, Julia, CSS, Objective-C, Clojure, Lua, C++, SQL, CoffeeScript


Sinatra, RubyMotion, Ruby on Rails (RoR), Cocoa, WebObjects, Padrino, Redux, Next.js, Django, UIKit, Tailwind CSS, Express.js, Stimulus, Spring, Hibernate, AngularJS, Angular


Node.js, React, Compojure, Rack, jQuery, Nokogiri, Xcode Server, Twitter API


Vim Text Editor, Jira, GitHub, GitHub Pages, Bitbucket, Emacs, TextMate, GitLab, Chef, Amazon Simple Queue Service (SQS), AWS Simple Notification Service (SNS), Quartz Composer, Xcode, Git, Mercurial, Reagent


Gang of Four (GOF) Design Patterns, Object-oriented Programming (OOP), Agile Software Development, Agile, Functional Programming, Kanban, Scrum, Distributed Programming, API Architecture, DevOps, Logic Programming


Android, Amazon Web Services (AWS), MacOS, iOS, Linux, FreeBSD, OS X, Heroku, Docker, JBoss, Visual Studio Code (VS Code)


SQLite, MySQL, PostgreSQL, Redis, Memcached, MongoDB


API Design, Architecture, API Integration, APIs, Software, Back-end, Mobile App Development, Software Development, Merb, Accounting Software, QuickTime, SANs, Code Architecture, Datomic, API Hooking, A/B Testing, Product Management


2008 - 2011

Doctorate in Computational Evolutionary Biology

Stevens Institute of Technology - New Jersey

2005 - 2008

Master's Degree in Chemical Biology

Stevens Institute of Techonolgy - New Jersey

1998 - 2002

Bachelor's Degree in Chemistry

Stevens Institute of Technology - New Jersey