SPID is an online database of two-hybrid protein interactions in B. Subtilis. Interactions stored in SPID are either characterized by experimental evidence or by bibliographic references.

A graphical user interface is provided to explore interaction networks as well as to view the details of each piece of evidence. The set of interactions accessible through SPID is determined by each user’s privilege levels. Only users with a private access are able to view the whole database and to interactively modify its contents.