Antispam prevents players from spamming on your server. This specific plugin includes the following ways of preventing spam:
Identical messages - Players cannot send identical messages Character spam - Players cannot send more than 3 identical characters in a row Caps lock - Players cannot send more than 5 uppercase letters per message or 40% uppercase letters
For the identical messages, only their last 5 messages are stored, this means after a player sends 5 nonidentical messages, they may repeat what they had said 5 messages ago.