Most sites log you out after a period of inactivity. Keep Every Page Alive reloads a page on a timer, and because each reload is a real request carrying your session cookie, the site's inactivity clock starts over — so the logout never arrives.
Enter the address of the site, choose an interval, and the page opens in its own tab and refreshes itself on schedule. Nothing to install, no account, and the whole thing runs in your browser.
https://mail.google.com.A surprising number of apps only renew your session on a request that arrives past the halfway point of the window — ASP.NET Core's cookie authentication is documented to re-issue the cookie only on “a request more than halfway through the expiration window”, and Salesforce ignores activity in the first half of its own window. Refresh too early against one of those and every request lands before it counts — the session expires exactly on schedule while the countdown here looks perfectly healthy. Two-thirds clears halfway with margin to spare. See the directory for per-app numbers.
The presets are ordinary minutes; the prime stagger option uses prime numbers between 17 and 887 seconds — primes rarely share factors, so several kept pages don't drift into refreshing in lockstep. You can also set any interval you like, from a second to a century, including leap days and leap years.
Everything below lives under Fine tuning in the panel, collapsed by default so a first visit stays simple.
The tab's own title shows a live countdown and a ⚠ if anything needs you, so a glance at the tab strip is enough. Your list can be exported and imported as a plain JSON file, and a link like keepalive.page/?url=example.com&every=10m arrives with everything pre-filled.