During the bidding, conventional calls must be alerted and explained to the opponents. Playing artificial bidding systems on BBO is not practical because explaining each alerted call is time consuming and therefore frustrating for all participants. BBOalert solves this problem. Artificial bidding sequences can be predefined in a table. Opponents get the explanation automatically and immediately. Explanations entered manually during the game are recorded for future use. This add-on is compatible with Linux, Windows and Android platforms. For more details visit project's site : https://github.com/stanmaz/BBOalert