JavaScript the page downloads but never uses Lighthouse: Reduce unused JavaScript · Est savings of 935 KiB · could save about 1.8 s
The server takes a long time to answer Lighthouse: Reduce initial server response time · Root document took 860 ms · could save about 0.8 s
The server takes a long time to send the first page Lighthouse: Document request latency · could save about 0.8 s
What it costs
Google calls 2.5 s or less good for the main content. instacart.com is 6.6 s past that on a mid-range phone.
Speed is money: in Deloitte's 2020 study Milliseconds Make Millions (37 brands, 30 million sessions), making a site just 0.1 s faster on phones went with 8.4% more orders for retail sites and 10.1% for travel sites. Most slow pages come down to one or two root causes.
Want it fixed?
We find the root cause across the browser, the network and the server, fix it,
and prove it with a before-and-after test. Start with a Diagnosis: a written root cause and a fix plan.