Open Badges are viewable digital documents, rich of information, that certify skills, abilities, belonging to groups, attendance to training courses or assignment of credits.
The Open Badges standard defines an open source format for packaging information (metadata) on the achieved results, and embedding them in a portable image file, that is unique for each recipient.
Information such as issuer, recipient, criteria to earn a specific badge, etc. can be read and verified in real time by all apps that complies with the standard.
Some metadata are mandatory, others are optional (Alignment, Revocation, Tag, etc.) and are used to better describe the context represented by the Badge.