How do I open a HAR file?

Open browser devtools with F12, go to the Network tab, and drag the .har onto it. Chrome, Edge and Firefox all render it as a browsable request list. It is JSON, so any editor also shows the raw contents.

Is it safe to share a HAR file?

Not by default. HAR captures headers including session cookies and authorization tokens, and form submissions including passwords. Sanitize it before sending, and never post one publicly.

File extensions

How to open a .har file

HTTP Archive · Diagnostic

A .har file is a recording of browser network traffic, stored as JSON. Open it in your browser devtools Network tab, or in any text editor. Treat it as sensitive: it usually contains session cookies.

What a .har file actually is

When support asks you to "send a HAR file", they want a log of every request the browser made: URLs, headers, timings and often response bodies. It is the standard way to diagnose a problem that only happens on your machine.

The format is plain JSON, so it is fully readable, and a dedicated viewer just makes it pleasant rather than possible.

Why it will not open

Nothing is associated with .har, and opening the raw JSON in Notepad is technically successful and practically useless because a single page visit produces tens of thousands of lines.

Renaming it to an extension you can open will not help: changing the extension does not convert the file, it only changes what Windows tries to open it with.

Step by step

Windows

01Best route: open Chrome or Edge devtools with F12, go to the Network tab, and drag the .har file onto it. The whole session renders as a normal request list you can sort and filter.
02Firefox devtools accepts the same drag-and-drop in its Network tab.
03For a quick look at the raw data, open it in VS Code, which formats large JSON without freezing.

macOS

01Identical: open devtools in Chrome, Edge or Firefox and drag the file onto the Network tab.
02Safari can export HAR but is less convenient for importing one.

What usually goes wrong

A HAR file usually contains your login session

HAR captures request headers, and that includes cookies and authorization tokens. Anyone holding the file can often replay your session. Before sending one to support, use the "sanitize" option if the tool offers it, and never post a HAR publicly on a forum or issue tracker.

It can also contain what you typed

If the recording covers a form submission, the POST body is in there, passwords included. Record only the steps that reproduce the problem, and start the capture after logging in where possible.

Programs that open .har

Our pick, in order. Every one links to the publisher's official download URL and the SHA-256 hash of the installer. Once you have downloaded it, you can check the file against our index before you run it.

If you end up downloading one of these from somewhere other than the publisher, what you can and cannot verify about that is worth two minutes.

Common questions

How do I open a HAR file?: Open browser devtools with F12, go to the Network tab, and drag the .har onto it. Chrome, Edge and Firefox all render it as a browsable request list. It is JSON, so any editor also shows the raw contents.
Is it safe to share a HAR file?: Not by default. HAR captures headers including session cookies and authorization tokens, and form submissions including passwords. Sanitize it before sending, and never post one publicly.