Is my HAR file uploaded anywhere?

No. The file is read and parsed entirely in your browser with JavaScript — nothing is sent to a server. That is important because HAR captures routinely include authorization headers, session cookies, and request/response bodies.

A HAR (HTTP Archive) file is a JSON record of the network requests a browser made, exported from the DevTools Network panel. It contains each request and response — URLs, headers, cookies, timings, sizes, and often bodies.

How do I export a HAR file?

Open your browser’s DevTools (F12), go to the Network tab, make sure recording is on, reproduce the page load or activity, then right-click any request and choose “Save all as HAR”. Chrome, Edge, Firefox, and Safari all support this.

What do the waterfall colors mean?

Each bar is positioned by when the request started and how long it took. The lighter leading segment is connection setup (DNS, connect, TLS, send), the mid segment is waiting for the server (TTFB), and the solid segment is downloading the response.

What performance issues does it flag?

Insights highlights failed requests (4xx/5xx), redirects, text assets served without gzip/Brotli compression, static assets with weak or missing cache headers, resources over 1 MB, requests slower than one second, and plain-HTTP requests.

HAR File Viewer & Analyzer

Open a HAR (HTTP Archive) file and explore every network request in a fast, filterable table with a waterfall timeline and a full headers / cookies / payload / response inspector. Switch to Insights for performance findings — slowest and largest requests, uncompressed assets, weak caching, redirects, and errors — or generate a printable report. HAR files contain auth headers, cookies, and request bodies, so this matters: the file is parsed entirely in your browser and is never uploaded.

How to use HAR Analyzer

In your browser DevTools, open the Network tab, reproduce the activity, then right-click → “Save all as HAR”.
Drag the .har file onto the Explorer (or paste the JSON) — it loads instantly, in your browser.
Filter by URL, domain, or resource type, and click any request to inspect its headers, cookies, query, payload, and timing.
Open Insights for aggregate stats and performance findings, or Report to print/save a PDF or download a standalone HTML summary.
Export the (filtered) requests to CSV or JSON with the toolbar buttons.

Frequently asked questions

Is my HAR file uploaded anywhere?: No. The file is read and parsed entirely in your browser with JavaScript — nothing is sent to a server. That is important because HAR captures routinely include authorization headers, session cookies, and request/response bodies.
What is a HAR file?: A HAR (HTTP Archive) file is a JSON record of the network requests a browser made, exported from the DevTools Network panel. It contains each request and response — URLs, headers, cookies, timings, sizes, and often bodies.
How do I export a HAR file?: Open your browser’s DevTools (F12), go to the Network tab, make sure recording is on, reproduce the page load or activity, then right-click any request and choose “Save all as HAR”. Chrome, Edge, Firefox, and Safari all support this.
What do the waterfall colors mean?: Each bar is positioned by when the request started and how long it took. The lighter leading segment is connection setup (DNS, connect, TLS, send), the mid segment is waiting for the server (TTFB), and the solid segment is downloading the response.
What performance issues does it flag?: Insights highlights failed requests (4xx/5xx), redirects, text assets served without gzip/Brotli compression, static assets with weak or missing cache headers, resources over 1 MB, requests slower than one second, and plain-HTTP requests.

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