GO Friend is an iPhone application developed by takumi suzuki. It is a free app in the Games category that allows trainers to find others who want to participate in Invitation Raid Battles.

The main feature of GO Friend is the "Invitation Raid BBS," which enables trainers to participate in raids around the world. Host trainers can report raids by tapping the "+" button at the top of the Invitation Raid BBS. They can enter raid information and the number of recruits needed, and then post it.

Guest trainers can search for active raids on the BBS. They can browse through raids reported worldwide and when they find one they want to join, they can tap "ENTRY." To join, they need to send a Friend Request to the Host trainer by copying their friend code. Once they receive an invitation from the Host trainer, they can join the raid.

With GO Friend, trainers can easily connect with others and participate in Invitation Raid Battles, expanding their gameplay experience in the Pokémon GO world.