If you use vim-vixen, consider giving tridactyl a try, it is one level above in terms of browser integration, I say this as an ex Vim-vixen user.

One example is using a custom search engine, with vim-vixen it'll just continue to use Google while tridactyl works fine, I also like how it highlights the elements targeted by the letters when you press 'f'

> One example is using a custom search engine, with vim-vixen it'll just continue to use Google while tridactyl works fine,

Hi,

I'm using vim-vixen with DuckDuckGo without problem. I just have "duckduckgo" set in search.default

What I call a custom search engine is something not in the default, like this one: https://searx.privatenet.cf/ I wasn't able to make it work, as a side note, I changed my search engine after installing vim-vixen, so its probably why it didn't work.