IronFox is Slow

IronFox was acting painfully slow. TTFB would sometimes be over a minute. Almost unusuable.

Investigation

First I started looking around at what others have ran into. Saw a few posts pointing towards extensions. I only had one installed, so that pointed me towards this issue about uBlock Origin.

The discussion pointed towards two possibilities, JIT being disabled for security reasons, and the fact the uBO has an incredible amount of rules enabled by default. I enabled JIT for extensions, restarted the browser, then tried a Web search. No joy.

Then I disabled the AdGuard, as a lot of what it covers should be in EasyList as well. I noticed a minor improvement, but if the load time was an entire minute, maybe this only saved a few seconds. Barely enough to be noticeable.

Some discussion in another issue focused on DNS over HTTPS. This seemed more likely, as the slowness appears to be before any response from the Web site, so it's likely something early in the request. I disabled Android's "Secure DNS" to see if that made any difference. No joy.

Some other posts suggested enableing Page Cache in IronFox's settings, but also no joy. That would only help with loading pages you've already visited, anyway.

Solution

I ended up going through all the IronFox settings just to see if I could find anything. Eventually I noticed IronFox had its own DNS over HTTPS settings. Thought this was odd, especially since the provider selected by default was Mulvad (with a Sweedish flag next to it!). Since I live in North America, this would no doubt add a ton of time to DNS resolution time.

I disabled DoH and just used the network/Android provided servers and that immediately resolved my issues. IronFox is usable, after who knows how long.