Rocket Page Speed Optimizer

Kinda works, but its highly inflexible (breaks other apps with no way of whitelisting them), the implementation is very weird, it updates your theme daily (or more) to change an expiry date. If this date is reached it wont work anymore, as a way to break it when you uninstall it. Generally this works completely without a server, so a one-time payment would make more sense. Instead they have a monthly fee for doing basically nothing after installing, other than messing with your theme.

Customer service also never answered my question for a way to whitelist scripts.

Better use another app, that ain't it.

I've been using this app for years, and it has improved my CWV scores. The customer service has been responsive and helpful as well.

It works really well at first, but with time, the speed starts dropping until it is tweaked again. Then it works for a short while and then again starts dropping. The customer service is bad: they may or may not respond. Sometimes there is no response for months. After checking other reviews I see that it's a common issue. It seems like the developers don't care for their app anymore. I'm going to discontinue their service.