An ISP proxy (also called a static residential proxy) is an IP address assigned by an internet service provider to a data center — combining the speed of datacenter infrastructure with the legitimacy of a residential IP. These IPs appear residential to target sites but are hosted on fast hardware.
ISP proxies sit between datacenter and true residential proxies on the speed-vs-detection spectrum: faster than mobile or rotating residential proxies, but less likely to be blocked than standard datacenter IPs. They are a good fit for tasks requiring both speed and low block rates — price monitoring, account creation, ticketing, and SERP data collection.