BYTETOOLS

HAR File Viewer

Open and analyze HAR files online — request table with method, status, size and timing, slowest-request and status-code stats, plus per-request headers.

Drop a .har file here or click to browseExport one from your browser DevTools → Network tab. The file is analysed locally and never uploaded.

What is the HAR File Viewer?

The ByteTools HAR File Viewer opens HTTP Archive (. har) files exported from Chrome, Firefox or Edge DevTools and turns them into a readable report: a request-by-request table with method, URL, status code, MIME type, transferred size and timing, plus summary statistics — total requests, total body bytes, the slowest request and a status-code breakdown.

  • Request table: method, URL, status, type, size, time
  • Totals, slowest request and status-code breakdown
  • Click-to-expand request/response headers
  • Live filter across URL, method and status
  • Handles large captures with row capping
  • 100% local — the HAR is never uploaded

How to use the HAR File Viewer

  1. 1

    Export a HAR from your browser: DevTools → Network → right-click → 'Save all as HAR'.

  2. 2

    Drop the .har file onto the viewer.

  3. 3

    Scan the summary stats and status-code breakdown.

  4. 4

    Filter by URL, method or status to find specific requests.

  5. 5

    Click a row to inspect its request and response headers.

About the HAR File Viewer

The ByteTools HAR File Viewer opens HTTP Archive (.har) files exported from Chrome, Firefox or Edge DevTools and turns them into a readable report: a request-by-request table with method, URL, status code, MIME type, transferred size and timing, plus summary statistics — total requests, total body bytes, the slowest request and a status-code breakdown.

Click any row to expand the full request and response headers for that entry, and use the live filter to narrow hundreds of requests down by URL fragment, method or status code. It is a quick way to inspect a session someone sent you without loading it back into DevTools.

HAR files can contain cookies, tokens and full URLs, so privacy is critical: this viewer parses the file 100% locally in your browser with no upload, no server and no analytics on the content.

Frequently asked questions

What is a HAR file?

HAR (HTTP Archive) is a JSON format that records every network request a browser made on a page — URLs, headers, status codes, sizes and precise timings. Support teams and developers use it to diagnose loading and API problems after the fact.

How do I create a HAR file?

Open DevTools (F12), go to the Network tab, reload the page so requests are captured, then right-click in the request list and choose 'Save all as HAR with content' in Chrome/Edge or use the HAR export icon in Firefox.

Is it safe to open a HAR file in an online viewer?

HAR files often embed cookies, auth tokens and personal URLs, so it matters where you open them. This viewer runs entirely in your browser — the file is read locally with the FileReader API and never transmitted — which is exactly why it is safe to use.

Why do some requests show no size?

Browsers record -1 or 0 for responses served from cache, blocked requests or entries exported without content. The viewer shows a dash rather than a misleading zero, and excludes unknown sizes from the transfer total.

Can I see why a page loaded slowly?

Start with the slowest-request stat and the time column — one hanging API call or a huge asset usually stands out immediately. The status-code breakdown also reveals failing requests (4xx/5xx) that may be triggering retries.

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