How to use the .tools HAR viewer

This is the hands-on tour of the viewer itself — where things are, what to click, and what the tool tells you about a capture. If you're new to the format entirely, start with the HAR guides at /har (what a HAR file is, how to generate one, why sanitizing matters) and come back.

Everything runs in your browser. The file is parsed locally, the secret scan happens locally, and the sanitized export is generated locally — you can load this page, go offline, and every feature below still works.

Open the free HAR File Inspector — no signup, runs entirely in your browser.

How to use it

  1. Drop a .har file onto the viewer (or click to browse) — requests, statuses, domains, sizes and timings break down instantly.
  2. Scan the diagnostics: failing statuses, slow responses and suspicious entries are flagged automatically.
  3. Open the secret scanner to see which cookies, tokens and keys the file is carrying.
  4. Pick your redactions — headers, cookies, query params, bodies, private IPs — and export the sanitized copy plus a Markdown report.

Why this one

  • Full breakdown: status codes, domains, MIME types, transfer sizes and timings.
  • Automatic diagnostics flag failures, slow responses and suspicious entries.
  • Secret scanner finds tokens and cookies before you share the file.
  • One-click sanitized export with a redaction report and cURL commands alongside the clean HAR.

Frequently asked questions

Is my HAR file uploaded to a server?

No. The viewer parses the file entirely in your browser with JavaScript — nothing is sent anywhere. You can disconnect from the internet after the page loads and every feature still works.

What does the sanitizer remove?

You choose: sensitive headers and cookies, query parameters, request and response bodies, and private IP addresses. It also emits a Markdown report and cURL commands alongside the clean HAR.

What's the biggest HAR file the viewer can handle?

There's no hard limit — the file is parsed in-memory by your browser, so multi-hundred-megabyte captures get slow but still work. For the best experience, keep captures focused on the failing action.

Where do I get a HAR file to analyze?

Capture one in your browser's DevTools — the /har guides walk through Chrome, Firefox and Safari step by step — or download the sample file linked there to try the viewer first.