Not really, the frontend caches the static parts of the template and the backend only needs to resend the dynamic, changing, parts. So "Welcome to $mysite, $us

Not really, the frontend caches the static parts of the template and the backend only needs to resend the dynamic, changing, parts. So "Welcome to $mysite, $username." would initially send the full rendering but if the data changes it would only send "Hacker News,lawik" over the wire. Somewhat simplified. This covers it quite well: https://www.youtube.com/watch?v=8xJzHq8ru0M https://www.youtube.com/watch?v=8xJzHq8ru0M