Comparison
Network waterfallvsRequest waterfall
Network waterfall
you looked at the timing bars and saw one request that could not start until three others had finished.
The network panel's view of every request as a bar positioned by start time and sized by duration. The shape carries the diagnosis: stair steps mean a dependency chain, a long pale segment before a bar means the request was queued or blocked, and a wide gap before anything starts means server time. It is the first place to look for a slow page and the last place most people look.
Full entry →Request waterfall
the second request could not start until the first finished, because the component that made it had not rendered yet.
Requests that run in sequence when they could have run in parallel, usually because a child component only mounts after its parent's data arrives. Each level adds a full round trip, so a three-deep component tree turns a 100ms API into a 300ms page. The fixes are hoisting the fetches, preloading at the route level, or letting the server render the whole tree at once.
Full entry →