Why is data validation important? What are effective ways to ensure data is valid? In this session we’ll explore how data validation is directly linked to security, stability and developer productivity when dealing with untrusted or unknown data sources. We’ll discuss the dangers of code that does not validate its data - everything from injection to DOS attacks. We’ll go hands on with joi (https://github.com/hapijs/joi) and Express (http://expressjs.com/) to see how data validation can make code easier to work with. No more "Uncaught ReferenceError" or if null checks littered around the code base. In the end, we’ll see how code can be secure, stable and magically awesome to work with.