# HAR File

The HTTP Archive format - HAR - is a JSON-formatted archive file format for logging of a web browser's interaction with a site. The common extension for these files is .har.

Typically data about timings is stored and can be used to generate a [waterfall](/glossary/w/waterfall) graph:

* Time to fetch DNS information
* Time for each object request
* Time to connect to server
* Time to transfer assets from the server to the browser of each object

HAR files can be generated by most browsers.