HAR File Viewer
Open a HAR file and read the captured network requests in a clear layout.
Making sense of a network capture
A HAR file is a recording of the network activity a browser captured — every request a page made, with its timing, headers, status and size — exported as JSON from developer tools. Raw, it is an enormous, unreadable blob. This opens a HAR file and lays out the requests clearly, so you can see what a page loaded, how long each request took, and where the problems are.
Drop in a HAR file and the captured requests are displayed.
What a HAR reveals, and a caution
HAR files are how performance and loading issues get diagnosed and shared: they show the waterfall of requests, which ones were slow, which failed, and how much was downloaded — often making the cause of a slow or broken page obvious. One important caution: a HAR can contain sensitive data, including headers, cookies and authentication tokens captured during the session, so it should be handled carefully and scrubbed before sharing. Because this opens it in your browser, the file is not uploaded anywhere to be read.
HAR File Viewer FAQ
What is a HAR file?
A recording of a browser's network activity — every request with its timing, headers, status and size — exported as JSON from developer tools.
Is there anything sensitive in a HAR?
Yes — it can contain cookies, auth tokens and headers from the session, so handle it carefully and scrub it before sharing.
Is my file uploaded?
No. The HAR is read in your browser, which matters given it can hold sensitive data.