Jose Castellanos, Developer in Fort Lauderdale, FL, United States
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Jose Castellanos

Verified Expert  in Engineering

Full-stack Developer

Fort Lauderdale, FL, United States
Toptal Member Since
February 21, 2020

Jose is a senior full-stack software engineer with an abundance of experience in front-end, back-end, and mobile development as well as server setup and infrastructure. He has served as technical leads on multiple projects and often handles complex issues that span across the tech stack. Jose takes pride in all the work he does and communicates effectively to find the best solutions for his clients. He values testing, maintainability, and safety of his code and architecture.


Airspace Technologies
Amazon Web Services (AWS), Heroku, AngularJS, React, CSS, HTML, Python...
MCM Construction
MacOS, Windows, Azure Active Directory, PHP, Linux, CSS, HTML, JavaScript...




Preferred Environment

Slack, Adobe Suite, WebStorm, PyCharm, DataGrip, Go, RubyMine, Android Studio, Xcode, Docker, MacOS, Linux

The most amazing...

...project I've worked on required learning Go to write an optimized microservice, which greatly reduced the number of servers needed.

Work Experience

Senior Software Engineer

2018 - PRESENT
Airspace Technologies
  • Designed, created, and tested microservices in Go and then integrated them which greatly increased our server performance and throughput allowing us to downscale our main servers while being able to maintain a higher throughput.
  • Contributed to the conversion of the front end from ERB/AngularJS to React.
  • Aided the QA in testing and product support concerning both our server and mobile applications.
  • Contributed heavily to both reactors and implemented new features on our main application (Ruby on Rails).
  • Performed code reviews on PRs for all of our applications across many different languages and frameworks.
  • Worked on and maintained our four mobile applications (driver app as well as client app for both Android and iOS) as well as the embedded Apple TV app.
  • Wrote scripts in Bash, Ruby, and Python that aided the team to be able to develop faster and automate tasks.
  • Dockerized applications to make it easier to test and develop as the engineering team grew.
  • Migrated apps to AWS from Heroku to save money and gain more control over the infrastructure.
  • Assisted product in creating both the high level and individual tasks in Jira to get the stories fully fleshed out for other developers to be able to work on.
  • Designed, created, and maintained APIs for the front end, mobile apps, and microservices.
Technologies: Amazon Web Services (AWS), Heroku, AngularJS, React, CSS, HTML, Python, JavaScript, Java, Swift, Go, Ruby on Rails (RoR), Ruby

Software Engineer

2014 - 2018
MCM Construction
  • Developed, managed, and maintained a robust intranet using Ruby on Rails running behind an Nginx web server on Debian.
  • Developed, managed, and maintained mobile applications (iOS and Android) which served both as an extension of the intranet and for unique tools to aid workers in the field at job sites.
  • Created a dynamic system using Ruby on Rails for admins to create forms and design workflows in order to greatly streamline the manual process of filling out and sending paper forms. Over 50 forms were successfully automated.
  • Wrote Ruby and Python scripts to analyze and consolidate data from ten different sources as well as scripts to automate email sending and specific tasks.
  • Developed, managed, and maintained the server API to power mobile applications. This was done first in PHP and later in Ruby on Rails.
  • Served as the sole engineer on the majority of the projects. This included project management, research and design, development, deployment, testing, and product support.
Technologies: MacOS, Windows, Azure Active Directory, PHP, Linux, CSS, HTML, JavaScript, Swift, Java, Objective-C, Ruby

Private Pass

I developed an application with a specific password generator that I made for personal use but decided to publish it to the iOS App Store. It uses AES 256 encryption to store key-value pairs whose values are hashed together to generate a unique password. This allows you to use words that are familiar to you to create a password that only appears to be random.
2006 - 2011

Bachelor's Degree in Biology and Chemistry

Florida State University - Tallahassee, FL, USA


Ruby ERB, Ruby on Rails API, JSON API, REST APIs, Rails Engines, Google Maps, Google Maps API, MobX, Devise, React, Node.js, CocoaPods, React Redux


Webpack, Docker Compose, Amazon Elastic Container Service (Amazon ECS), RubyMine, GoLand, Android Studio, RVM, Xcode, Git, Slack, PyCharm, WebStorm, DataGrip, Node Version Manager


Ruby on Rails 4, Ruby on Rails 5, Ruby on Rails (RoR), Cocoa Touch, Ruby on Rails 3, Android SDK, RealmSwift, Core Data, Redux, Flutter, React Native, AngularJS


iOS, Heroku, Amazon EC2, Android, Linux, Docker, Firebase, MacOS, Adobe Suite, Windows, Amazon Web Services (AWS)


Go, Swift 1, Swift 2, Swift 3, Swift 4, Ruby, JavaScript, Swift, Swift 5, Java, HTML, CSS, XML, SQL, TypeScript, Dart, Kotlin, Objective-C, PHP, Python


JSON, PostgreSQL, Amazon S3 (AWS S3), PSQL, MySQL, Realm, SQLite, Redis, Azure Active Directory, Microsoft SQL Server


Kanban, Agile


APIs, Back-end, Rails Asset Pipeline, Webpack Rails Integration, Ruby Gems, Front-end, SOAP

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