The HTTP Archive format, or 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.
The specification for the HTTP Archive (HAR) format defines an archival format for HTTP transactions that can be used by a web browser to export detailed performance data about web pages it loads. The specification for this format is produced by the Web Performance Working Group of the World Wide Web Consortium (W3C). This document was never published by the Web Performance Working Group and has been abandoned.
The HAR format is supported by various software, including: