#  >  > Networking, Hardware, Server Side Technologies >  >  > Networking and Hardware >  >  > Server Side Technologies >  >  What is ETag and how does it works?

## Lorraine

An ETag is an opaque identifier assigned by a web server to a specific version of a resource found at an URL. If the resource content at that URL ever changes, a new and different ETag is assigned.



In typical usage, when an URL is retrieved the web server will return the resource along with its corresponding ETag value, which is placed in an HTTP ETag field.

What is the process of working in these ETags?

Thank you.

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