I've been trying for about a year to get off gmail, but the search is just too good and I keep finding myself with roundcube open in one window and gmail in the other. This really started as just seeing if I could replicate gmail's search, but I wound up building it into a pretty fully featured webmail application. https://github.com/grahamsz/rolltop https://rolltop.app Search is really fast! Even running it on my ancient Synology NAS it can search my 100k message account in about a quarter second.