The Netflix API is the front-door for almost all device/UI requests from 1000+ device types to the Netflix backends. It serves everything from movie and show recommendations, profile, sign-up, and A/B test related functionality, to bookmarks and licenses for playback.

Because all devices use this API, and because Netflix runs on devices of widely varying sizes and interaction models, it has served us well to enable a platform against which device teams write server-side scripts. Using Netflix as an example, the goal of this talk is to explore situations in which server-side scripting is a good solution for applications. I will describe our first approach, which uses Groovy scripts. I will detail how the scripts are uploaded and can make use of shared modules. This approach allows for high flexibility and performance as well as high developer velocity, at the expense of added risk of injecting scripts into running servers. I will then dive into a new approach that will isolate the scripts into their own containers without compromising the original goals and will allow teams to write scripts in node.js, a language that is more natural for them.