Understanding what is requested.
WHAT THE NETWORK PANEL SHOWS
Every request made Its status Its size, transferred and uncompressed Its timing, broken into phases Its headers
WHAT TO LOOK FOR
Requests failing Requests far larger than expected Requests nobody intended Requests made repeatedly Slow phases
WHAT THE TIMING BREAKDOWN REVEALS
Whether time went to waiting for the server, or to transferring.
WHY THAT MATTERS
They require entirely different fixes.
WHAT TO CHECK FOR CACHING
Whether responses are served from cache, and what headers were sent.
WHY
Caching configured incorrectly is invisible without looking.
WHAT TO ENABLE FOR REALISTIC TESTING
Throttling, simulating a slow connection Cache disabled, to see first-visit behaviour
WHY THROTTLING MATTERS
Development on a fast connection conceals every performance problem.
WHAT TO SORT BY
Size, to find the largest contributors Time, to find the slowest
WHAT TO EXPORT
The record, for sharing with someone else.
WHAT TO CHECK ON ANY SLOW PAGE
The total transferred, and the largest single item.
