Turn a HAR capture into useful evidence

A HAR is a record of what a browser observed—not a packet capture and not a complete explanation of why a request failed.

Capture a short, relevant interval

In Chromium-based browsers, open Developer Tools, choose Network, reproduce the issue and export a HAR using the browser’s sanitized option when available. Avoid unrelated browsing during the capture. Follow your organization’s rules before capturing private systems.

Chrome’s sanitized export removes sensitive headers such as Cookie, Set-Cookie and Authorization. Other secrets can remain in URLs, request bodies, response content and custom fields. Sanitized does not mean anonymous. Never post a raw capture publicly just because it has that label.

Keep the capture local

Network Goblin reads only the file you select, up to 8 MiB and 5,000 entries. It does not upload, persist, replay or fetch its requests. Captures are kept in page memory until cleared or the page closes. The sample is fabricated traffic for demonstration, not a measurement of your connection.

Look at status and duration together

HTTP 4xx and 5xx responses identify requests worth reviewing, not necessarily the root cause of a page problem. HTTP 3xx responses cover redirection and cache-related responses such as 304 Not Modified. They are not automatically errors. A missing or zero status is shown as “No HTTP status”; it is not assigned a made-up network error. Requests are ordered by their reported duration.

Duration comes from each HAR entry’s time field. Unknown and negative values remain unknown. Requests overlap, so a request-time percentile is not page-load time. Body sizes come from recorded response bodySize values and exclude headers, transport overhead and unknown sizes. They are not a full wire-transfer estimate.

Share less, deliberately

Paths and hostnames shown locally can still identify people or internal services. The exported summary is newly constructed from counts and numeric metrics. It omits hostnames, URLs, IP addresses, headers, bodies and raw extension fields. It is a smaller disclosure, not a promise of anonymity. Review it before sharing, and use an approved secure channel if support truly needs the original HAR.

Sources: Chrome HAR export, Chrome Network reference, Local browser File API.