1. A computer-implemented method for composing a valid HTML document using template transclusion, comprising: retrieving a transcluded template file including a transcluded template; retrieving a transcluding template file including a transcluding template, the transcluding template including credentials to the transcluded template; validating that a data-type of an input parameter in the transcluding template matches a data-type of the transcluded template; building a binary transcluded template object from the transcluded template and a binary transcluding template object from the transcluding template based on the validating; and uploading the binary transcluded template object and the binary transcluding template object to a server to generate the valid HTML document that is sent for display on a browser, wherein content in the valid HTML document associated with the transcluded template is included within content in the valid HTML document associated with the transcluding template.