Open a .har network export: requests, sizes, slow and failed calls, a copy without secrets
Processed in your browser. Nothing is uploaded. Checked against sources on 17 Oct 2026.HAR File Viewer opens a browser network export (.har, up to 300 MB) in your browser and shows the number of requests, bytes transferred, load time, the 10 slowest and largest requests, failures and every domain contacted. It saves the list as CSV and writes a clean copy without cookies or tokens. Nothing is uploaded.
Save the HAR in the browser: Network tab, then Save all as HAR (or Export HAR).
Press Select a HAR file, or drop it on the page; it is read on your device.
Read the totals, the slowest and largest requests, failures and the domains contacted.
Download the request list as CSV, or a cleaned HAR with cookies and tokens removed for sharing.
A HAR (HTTP Archive) file is what a browser's network panel saves: every request a page made, with headers, sizes and timings. Support teams ask for one when a site misbehaves, and developers save them to find what is slow. Opening one usually means loading it back into developer tools; this page reads it directly.
What you see.
| Figure | Where it comes from |
|---|---|
| Requests, transferred, size | Each entry's transfer size (or headers plus body), and the decoded size |
| Load | The page's onLoad time, and the span from the first request to the last response |
| Slowest 10 and largest 10 | Each entry's total time and transfer size |
| Failed and redirected | Status 0 (blocked or cancelled), 4xx and 5xx; 3xx |
| By type and by domain | Document, script, style, image, font, media, XHR; each host with its requests and bytes |
Requests served from the browser cache show 0 bytes transferred and are marked as such.
Share it safely. A HAR holds your cookies and login tokens in plain text. Download clean HAR replaces every cookie value, the Authorization, Cookie, Set-Cookie, API-key and CSRF headers, tokens, codes, signatures and passwords in URLs and form posts with [removed]. Bodies can be removed too. Status codes, timings and sizes stay, so the copy still shows the problem.
Export. The request list saves as a CSV with method, URL, status, type, MIME type, bytes, time, waiting time, start and cache status, ready for Excel.
Tested with a Chrome-shaped export and 300 generated files whose totals are recomputed a second way, and whose planted secrets must all be absent from the clean copy. Nothing is uploaded.
Drop the .har file on HAR File Viewer. The number of requests, the data transferred, the load time, the slowest and largest requests, failures and the domains contacted appear at once, read in your browser. No developer tools or extension are needed, and it works on any computer or phone.
Open the page, press F12 to open developer tools and choose the Network tab. Reload the page so every request is recorded, then right-click the request list and choose Save all as HAR with content. Firefox calls it Save All As HAR; Safari, Export HAR.
Not as saved: a HAR includes your cookies and login tokens, which can let someone use your account. Download clean HAR here first. Cookie values, Authorization and API-key headers, and tokens or passwords in URLs and forms are replaced with [removed], while timings and status codes stay.
Look at the Slowest list. A long Waiting time means the server took long to answer; a large Transferred figure with a long time means a heavy file. The By domain table shows third-party hosts, such as ads or analytics, that add requests and time.
Status 0 means no response arrived: the request was blocked by an ad blocker or browser policy, cancelled, or failed to connect. Statuses from 400 to 499 are client errors such as 404 Not Found or 401 Unauthorized, and 500 to 599 are server errors.
No. The file is read by your own browser, and the CSV and the clean copy are written on your device. A HAR holds private data such as cookies and the pages you visited, and none of it reaches a server.
Rates and rules change; check the source before you rely on a figure.
Still stuck? Ask about HAR File Viewer and anybody who knows can answer. No account needed.
Same job, other tools: Flow Video Renamer – Rename Google Flow clips in story order, without their timestamps · Remove Timestamp from File Names – Strip the date and time from hundreds of file names in one go.