1. A method comprising: storing a template in a source code format, wherein the template comprises instructions that can be dynamically executed to render a web page; identifying a first location within the template; determining a first encoding context for the first location, wherein the first encoding context comprises at least one encoding format that can be properly received at the first location; and verifying, based on the template, whether an error would occur based on a first set of filters already existing at the first location.