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HAR File Analyzer

Open a .har file to see every request with status, timings, redirects, server IPs, headers and security headers. Parsing happens entirely in your browser.

Processed locally. Your file is never uploaded.

What is a HAR file?

A HAR (HTTP Archive) file is a JSON log of everything a browser did while loading a page: every request and response, with headers, status codes, cookies, timings, the server IP it connected to and, optionally, response bodies. Support teams ask for HAR files because they show exactly what the browser saw, which screenshots and console errors often don't.

How to read the results

  • Status: 2xx success, 3xx redirect, 4xx client or policy errors (403 often means a proxy, WAF or CASB blocked it), 5xx server failures. 0 means no response was received at all.
  • Server IP: the address the browser actually connected to. Use it to spot traffic going through a proxy or a stale DNS answer.
  • Timing: long Wait (TTFB) points at the server or the proxy in between. Long Connect or TLS points at the network path, which you can check with our MTR tool.
  • Redirect chains: loops between an identity provider and the app usually mean a cookie isn't being saved or sent.

HAR analysis for Zscaler, Palo Alto and SSO issues

Proxy, CASB and VPN problems show up clearly in a HAR file: block pages and 403s from URL filtering, authentication redirect loops, failed TLS connections caused by SSL inspection, and the server IP proving whether a request went through Zscaler or Prisma Access. Read our guide to HAR file analysis for Zscaler and Palo Alto, and use Sanitize before attaching a HAR to a support case.

Frequently asked questions

Is my HAR file uploaded to your server?

No. The file is read and parsed by JavaScript in your browser tab. Nothing is sent to HardcoreDebug, and closing the tab discards it.

How do I capture a HAR file?

In Chrome or Edge, open DevTools (F12), go to the Network tab, tick Preserve log, reproduce the problem, then right-click the request list and choose Save all as HAR with content. In Firefox, use the gear icon in the Network panel and choose Save All As HAR.

Why do some requests show status 0 or (failed)?

Status 0 means the browser never got an HTTP response. Common causes are the request being blocked by an extension or proxy, a DNS or TLS failure, CORS rejection, or the request being cancelled during navigation. Check the error text in the Overview tab.

Is it safe to share a HAR file?

HAR files often contain session cookies, bearer tokens and form data. Use Download sanitized HAR to strip cookies, authorization headers and token-like parameters before sending one to a vendor or colleague.

What does the waterfall show?

Each bar starts when the request was sent relative to the first request in the file, and its length is the total request time. Hover a row to compare. In the Timing tab the time is split into blocked, DNS, connect, TLS, send, wait (TTFB) and receive.

Is this HAR analyzer safe for Zscaler or Palo Alto support files?

Yes. The file is parsed entirely in your browser and never uploaded. Use Sanitize to remove cookies, tokens and passwords before you send the HAR to Zscaler, Palo Alto or any other vendor.

How do I open a HAR file?

Drop the .har file onto this page, or click to choose it. Chrome, Edge, Firefox and Safari exports all work.