Save a network log

A network log (a "HAR file") records everything a page asks for and what came back. Web people ask for one when something fails to load or a form won't send.

Send it only to someone you trust

A network log can include the pages you visited during the recording and, sometimes, what you typed into forms. Record only the problem, use a private window where you can, and send the file only to the person fixing the site, never in a public post.

The Network tab, with Preserve log checked and the download arrow for Export HAR highlighted ElementsConsole Network Preserve log Check Preserve log, then the download arrow saves the file.
Chrome and Edge's Network tab. Firefox and Safari look similar.

Chrome or Edge on a computer

  1. Open the page and press F12 (Mac: ⌘ + Option + I). Click the Network tab.
  2. Check Preserve log, so nothing is lost if the page reloads.
  3. Reload the page and do the thing that goes wrong.
  4. Click the download arrow, Export HAR (sanitized). "Sanitized" leaves out your cookies and sign-in details, which is what you want.

Firefox on a computer

  1. Open the page and press Ctrl + Shift + E (Mac: ⌘ + Option + E). The Network tab opens.
  2. Reload the page and do the thing that goes wrong.
  3. Right-click in the list of requests and choose Save All As HAR.

Safari on a Mac

  1. Turn on the developer menu once: Safari › Settings › Advanced, check Show features for web developers.
  2. Open the page, press ⌘ + Option + I and click Network.
  3. Reload the page, do the thing that goes wrong, then click Export.