what is httphandler in asp.net?

Httphandler is used to handle specific request based on it’s extension. The most handler is asp.net page handler that process .aspx file. When user request an .aspx file, the request is processed by page through page handler. You can create your own http handler that render custom output to browser.

Types of httphandler:-

1.)   ASP.Net Page Handler (.aspx ):- The default handler for all asp.net page.

2.)   Web Service Handler(.asmx):- The default HTTP handler for Web service pages created as .asmx files in ASP.NET.

3.)   Generic Web Handler(.ashx) :- The default HTTP handler for all Web handlers that do not have a UI and that include the @ WebHandlerdirective.

4.)   Trace handler (trace.axd) :- A handler that displays current page trace information.

Note:- References from MSDN.