David Celis

+1 813.468.9737

I'm a full-stack web developer who specializes in architecting elegant APIs with an eye towards usability and maintainability. I am passionate about beautiful, readable code and believe strongly in community-driven coding standards. When I am not writing products that directly benefit other engineers, I'm an avid Open Source Software advocate. I maintain several open source libraries and have contributed to many more, including Ruby on Rails, bundler, Discourse, Hanami, and fish.


Code: Ruby, Rails, GraphQL, SQL, JavaScript

Tools: PostgreSQL, MySQL, Redis, Docker, git


HashiCorp November 2017 - Now Senior Software Engineer

I work on the enterprise version of HashiCorp's Terraform tool. Terraform is a free and open-source utility that allows engineers and teams to automate the process of provisioning infrastructure by defining that infrastructure as code. Terraform Enterprise (TFE) is a Ruby on Rails application that comes in both SaaS and private-install flavors. I'm responsible for working on TFE's backend API, its integration with Sentinel (an embeddable policy-as-code framework) and,occasionally, tinkering with its Ember.js frontend or its surrounding Go microservices. At HashiCorp, I have already lead several large projects, including preparing version 2 of the API for exiting its beta status, a new administration API for private TFE, and Policy Sets , one of the most-requested features from HashiCorp's customers.

GitHubStaff January 2016 - October 2017 Ecosystem Engineer

As a member of GitHub's Ecosystem Engineering organization, I was responsible for building and maintaining GitHub's developer APIs, third-party integrations, webhooks, and developer documentation. I was a member of the team that shipped the pre-release of GitHub's GraphQL API. After that, I spent my time on the Identity Access Management (IAM) team shipping Business accounts and GitHub Apps. I also onboarded myself onto GitHub's main on-call rotation after only three months on the job. At my last performance review, I was told that my on-call logs were consistently amongst the best at the company.

IMMUNIO April 2015 - December 2015 Software Engineer

At IMMUNIO, I designed the Ruby API that powered their front-end Angular dashboard. I also helped implement features to aggregate data on customers' most important security vulnerabilities. Prior to this project, suspicious events would be displayed in long, paginated lists. I worked closely with the front-end developer to roll up suspicious events into clear, ongoing attacks so customers could easily find them and fix them in their application's code base.

DigitalOcean August 2014 - March 2015 Software Engineer

I helped improve response times by hundreds of milliseconds in some of the least performant Cloud dashboard pages and developer API endpoints. I also worked on an effort to re-implement and re-design DigitalOcean's DNS product. DigitalOcean's backend was previously a series of Perl scripts running in a loop. As part of a larger effort to re- architect their backend as a network of Go microservices, I aided the rewrite of DNS so I could gain experience in Go. Finally, I was part of a team focused on improving the usability and functionality of various internal tools, including a custom CMS used heavily by their Customer Support team.

New Relic October 2012 - August 2014 Senior Software Engineer

I worked on the customer-facing dashboard for their flagship product, the APM dashboard, which received billions of metrics from millions of applications each day. My team developed popular features such as Key Transactions and X-Ray sessions. After acting as the PM on a minor feature, I joined an internal effort to lay the foundations for New Relic to migrate to a service-oriented architecture, developing several identity services.

DECK Monitoring May 2011 - July 2012 Software Engineer

I worked on a dashboard to display solar energy usage and generation metrics to thousands of residential and business customers who would report 100-200 pieces of data each minute. My major contribution to DECK Monitoring was the automation of reporting this data to California utility companies on behalf of customers seeking tax benefits.


goodbre.ws January 2011 - March 2014

goodbre.ws was a project borne out of my last year in the Rollins College Computer Science department. As a senior in the honors program, I was expected to produce, present, and defend an exceptional capstone project for and to the faculty. I chose to build my own collaborative filtering system based on the Jaccardian Similarity Coefficient. To provide a practical application for this system, I created goodbre.ws, a recommendation website for beer written in Ruby on Rails. The site was unexpectedly featured on Lifehacker and The Huffington Post.

Recommendable January 2012 - Today

Recommendable is a Ruby library that I extracted from goodbre.ws. It is a drop-in recommender system for Ruby applications using Likes and Dislikes. Ratings and recommendations are stored in Redis to utilize fast set mathematics for collaborative filtering.

Crepe September 2013 - Today

Crepe is a lightweight API framework designed to help you write clean, fast web services in Ruby. With an elegant and intuitive DSL inspired by RSpec, and with a nod to Grape, Crepe makes API design simple. Originally written by my brother and a friend of his, I joined as a maintainer in 2013 as I began to provide pieces to Crepe's ecosystem such as Creperie (a project generator and CLI) and a plugin to report performance metrics to New Relic.

rack-console July 2014 - Today

rack-console is a Ruby gem to provide an interactive Ruby interpreter for any Rack-based web application. Think of it like rails console for everything but Rails.

Sunscreen July 2014 - Today

Sunscreen is a macOS app that I wrote for fun. It's a lightweight menu bar app that changes your desktop wallpaper based on local sunrise and sunset times. Sunscreen was my first (of hopefully many) forays into Swift and developing in Apple's Xcode development environment.


Rollins College 2007 - 2011 Computer Science, B.A.H.

I graduated summa cum laude with a B.A.H in Computer Science. I graduated in the top 5 of my class with a 3.99 GPA (4.0 Major GPA) and was on the President's List for all terms.