KDBX is a file format native to KeePass Password Safe, a multi-platform password management tool.

KDBX is a database file that stores logins and passwords/passphrases. KDBX uses strong encruption algorithms to ensure secure data storage. KDBX format replaced older KDB format used by KeePass versions older than version 2. KeePass is a portable tool that doesn’t require to be installed on operating system. KeePass along with KDBX files can be easily stored on external storage devices.