Simon Santiago Soriano, Developer in Amsterdam, Netherlands
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Simon Santiago Soriano

Verified Expert  in Engineering

Software Developer

Amsterdam, Netherlands
Toptal Member Since
June 10, 2015

Simon is a software engineer with over six years of experience in the back end, distributed systems, CI, and web development. An ex-Uber employee and a founder of, Simon has co-authored the paper "Keeping Master Green at Scale" (published at EuroSys '19) and created two 5-star rated courses about Ruby and Ruby on Rails for Platzi, the largest online tech school in Latin America.

Amazon Web Services (AWS), Sidekiq, React, Ruby on Rails (RoR), Ruby
Java, Python, Bash, Agile Software Development
Amazon Web Services (AWS), Heroku, PhoneGap, Ionic, Ruby on Rails (RoR), Ruby




Preferred Environment

Command-line Interface (CLI), Sublime Text, Atom, Git, Ubuntu, MacOS

The most amazing... I've done was at Uber—I led the development of remote execution and caching for the build system, achieving 2x build time improvements in 50% of CI jobs.

Work Experience

Founder and Lead Developer

2015 - PRESENT
  • Optimized slow queries and page load time, leading to a 500% performance boost.
  • Developed a reservations module using React.
  • Migrated the app from Heroku to a Flynn cluster in AWS.
  • Architected the MVP for Salonomi.
Technologies: Amazon Web Services (AWS), Sidekiq, React, Ruby on Rails (RoR), Ruby

Senior Software Engineer

2017 - 2020
  • Led the development and implementation of remote execution and remote caching for the build system, achieving two times build time improvements in 50% of CI jobs for the largest repository in the company.
  • Co-designed and co-developed a test analysis platform capable of processing millions of test results per hour.
  • Co-authored "Keeping Master Green at Scale" paper, published at EuroSys '19.
Technologies: Java, Python, Bash, Agile Software Development

Software Engineer

2016 - 2016
  • Developed an MVP of a mobile application using Ruby on Rails for the back end, Ionic for the front end, and PayPal and Stripe as payment gateways.
  • Built new features and fixed bugs for a Point of Sale System developed using Ruby on Rails, ActiveAdmin, and Ionic.
Technologies: Amazon Web Services (AWS), Heroku, PhoneGap, Ionic, Ruby on Rails (RoR), Ruby

Software Engineer and Mentor

2015 - 2015
Make It Real Camp
  • Developed a code evaluator module using Docker containers, Dokku, and Sidekiq. This module can evaluate HTML, JavaScript, Ruby, and even Rails projects.
  • Oversaw code maintenance, deployment, continuous integration, monitoring, and overall performance of the platform.
  • Designed and implemented code challenges for the web development learning platform.
  • Implemented new features for the web development learning platform.
  • Recorded screencasts about web technologies.
Technologies: Amazon Web Services (AWS), Heroku, DigitalOcean, Sidekiq, Dokku, Docker, RSpec, Ruby on Rails (RoR)

Software Engineer

2014 - 2015
  • Led the development of Datapagos, a payments platform for Colombia.
  • Developed the back end as a RESTful API with Ruby on Rails.
  • Migrated the front end from Ruby on Rails to AngularJS.
  • Implemented integration with two payment processors.
  • Managed the deployment and development using AWS.
Technologies: Amazon Web Services (AWS), SOAP, RSpec, Angular, Ruby on Rails (RoR)

Software Engineer

2014 - 2014
PayU Latam
  • Extended a payment platform that supports over 90% of online payments in Colombia and over 40% of online payments in Latin America.
  • Refactored unit tests that looked like integration tests.
  • Created test fixtures for almost every class I touched.
  • Reduced the execution time for tests.
  • Implemented a new payment method.
Technologies: Spring, Java

Founder and Software Engineer

2013 - 2014
  • Developed two mobile applications financed by the Colombian government.
  • Constructed Yo Reporto, an app that lets Colombians report natural disasters in their vicinity.
  • Developed APIs using Node.js.
  • Built a module that renders statistics using PhoneGap and Google Charts.
  • Supported Android and iOS.
Technologies: Heroku, JavaScript, Node.js, PhoneGap

Slack Visitor
Slack Visitor is a Slack app that lets you accept chats from Slack outsiders through a web client that you can embed on your web page. Useful for teams that want to provide chat support directly from Slack.

Toptal Open Source Grant

Recipient of the first Toptal Open Source Grant.

Selected Open Source Contributions
I've made contributions to Ruby, Go, Rust, Bash, and JavaScript to different projects ranging from native extension libs to SDKs and PaaS.



Fast Priority Queue
Developed a Ruby native extension written in Rust that implements a priority queue 130 times faster than a pure Ruby implementation.


My team won AngelHack Bogota 2016 building, an application that lets you save, share, and search for data through a Slack command and a web dashboard.

Date Supercharger
Date Supercharger is a gem that adds _between, _between_inclusive, _after, _after_or_at, _before, and _before_or_at methods to every date/datetime field of Active Record models.


Web application to administrate accreditations and courses offered for the Red Hat Latam Partner Enablement Team.

Developed using Ruby on Rails.

Suppliers Admin Platform

Web application to manage the suppliers of a five-star hotel.

Developed using Ruby on Rails.


Heroku has released new tiers where free features are becoming thinner and thinner. We provide a solution by helping you switch easily between two servers, and therefore helping you maintain freedom forever.

Competitive Programming Network | Contest Registration Site
Competitive Programming Network reunites more than 300 contestants monthly from all around the world. As a volunteer, I'm developing the web application that handles team registrations.

Chrome Dev Tools Article

Article about Chrome DevTools.

Yo Reporto

App that lets Colombians report natural disasters in their vicinity. The development was financed by the Colombian government and the app has 4.4 stars in Google Play.

Programming Competitions

WINNER: Colombian collegiate programming league. (Best results: First and third place)

TOP 10: Participated in four qualifying rounds for the ACM ICPC regionals. (Best results: 7th and 9th place out of 109 teams)

MENTOR: Trainer for a university rookie programming marathons team (2011 - 2013)
2009 - 2014

Bachelor's Degree in Computer Science

Pontifical Xavierian University - Colombia


REST APIs, React Redux, React, Node.js, jQuery, Sidekiq, Vue


Git, Atom, Sublime Text, RSpec, GitHub


Ruby on Rails 4, Ruby on Rails (RoR), Ruby on Rails 3, Spring, PhoneGap, Ionic, Angular, Chrome


Ruby, JavaScript, Python, TypeScript, Go, SCSS, HTML, Java, CSS, Markdown, Bash, ECMAScript (ES6), Rust


Agile Software Development, Scrum, Test-driven Development (TDD)


Ubuntu, Amazon Web Services (AWS), Docker, MacOS, DigitalOcean, Heroku, Dokku, Google Cloud Platform (GCP), Unix


PostgreSQL, Redis


Command-line Interface (CLI), SOAP, Computer Science, SSH

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