Fastly's tech stack

Our philosophy on toolsets is “the right tool for the job.” Mostly, we’re a Unix shop, and the languages and frameworks we have in production are the following:

• Varnish (obviously) for caching, which is developed in C
• Ubuntu OS with some heavy modifications to better optimize SSD usage
• BGP for network routing
• Apache for serving web objects and terminating SSL
• Perl for our control plane and VCL deployment
• Assembly in our control plane for an extra boost
• Go for our streaming logs and stats, our video handling, and more
• Ruby/Sinatra for our public API
• Python for purging/cache invalidation and system health
• Backbone.js for our front end app
• Coffeescript/Sass on the front end
• Epoch for data visualization
• Chef for deployment automation and config management
• Jekyll for our www.fastly.com site
• Jenkins for job scheduling and automation
• Ganglia for system monitoring

In addition, most tools in our stack have been altered and optimized for a distributed, highly performant environment. If we need something improved or changed, we do it. If another tool, language, or framework solves the job better, we use it.