What websites/apps do German men use to hookup?

[Bart]

I'm want to visit Germany again in December (most likely Cologne). I was last month in Essen to visit the two bath houses there, but I didn't know how to find hookups. In The Netherlands there's a well known gay chat website that is used and I wondered how German men find hookups.  

[pozlondonfucker]

Gayromeo and Barebuddy

Also Grindr and I've found Sniffies is beginning to be popular in some of the larger cities but probably 50% tourists.