What is waiting TTFB in Chrome?

With the Developer Tools window visible, click the menu icon (the three vertical dots in the top right corner) and click Settings. Chrome Version 86 the setting is on the same place but named differently, so: Settings -> Preferences -> Global -> Auto-open DevTools for popups .

How to Measure Your TTFB

Additional TTFB check methods (using a web browser)

More clearly TTFB is also called “waiting” by Google: Time spent waiting for the initial response , also known as the Time To First Byte. This time captures the latency of a round trip to the server in addition to the time spent waiting for the server to deliver the response.