Analyse HAR files.
Without going online.
No web server, account, installation, CDN, telemetry or network connection needed. Choose a HAR file from your computer and examine slow requests, HTTP errors and response size.
🔒 Runs locally · Never uploads HARs · No external assets · Works from disk
Analyse an HTTP Archive
Choose a .har file, up to 50 MB and 20,000 requests. The browser processes its contents locally.
No HAR data loaded.
Privacy: A raw HAR can contain cookies, credentials, tokens, personal data, request bodies and responses. Do not share the original capture without reviewing it. Generated reports still reveal some hosts and URL paths.
Analysis dashboard
Top hosts by cumulative duration
Potential problems
Requests — slowest first
| Method | Status | Sanitised URL | Duration | Size | Wait |
|---|
Verify offline network activity
OFFLINE EDITION · SELF-CONTAINED · NO CONNECTION REQUIRED
This one HTML file contains the analyser, its styling and the Mightora logo. It works directly from disk without external libraries. Its Content Security Policy blocks outbound fetch, XHR, frames and external scripts, styles and images.
Observed destinations
- Check when the page has loaded.
Scope: The Resource Timing API reports the resource loads exposed to this document, not every network request. The initial document, extensions, blocked requests and browser background services might not appear. Use Developer Tools for a more thorough check.
How to verify independently with F12
- Open Developer Tools using F12 or Ctrl+Shift+I (Windows/Linux), or Command+Option+I (Mac).
- Open the Network tab, select All, enable Preserve log and confirm recording is enabled.
- Reload the file. When launched directly using
file://, the HTML file itself is local and there should be no external script, image, font or stylesheet downloads. When launched over HTTPS, the initial HTML download is expected. - Select a HAR and analyse it. The Network panel should not show HAR uploads or any application HTTP requests. You can filter by Fetch/XHR to help identify them.
- Investigate any unexpected request; browsers and extensions can generate traffic outside this page’s control. For stronger assurance, disconnect from the network before opening a confidential HAR.
Do not share unreviewed DevTools logs: unrelated captured requests may contain sensitive data.
How to analyse a HAR file offline
In Chrome, Edge or Firefox, open Developer Tools → Network, reproduce the issue, then export the capture as a HAR file. Open this HTML file in a browser and choose that capture. HTTP 4xx and 5xx responses can indicate failed calls; long wait times suggest delays before the first byte; large responses can affect transfer time.
DNS, connection and SSL measurements depend on the browser that recorded the HAR. Aggregate host durations are the sum of overlapping request timings, not actual page load time. P95 is calculated from the request durations in this particular capture.
Privacy and frequently asked questions
Will this upload my HAR file?
No. This single HTML file has no remote scripts, stylesheets, images or analytics, and no HAR upload code. Open it with networking disabled to confirm that it works offline.
Can I share exported findings?
Use the sanitised JSON export, but inspect it before sharing. It excludes raw headers, cookies, query strings and response bodies, but hostnames and some URL paths remain.
Can it be installed?
No installation is needed. Keep this HTML file somewhere convenient, and open it directly in Chrome, Edge or Firefox.