An open file format is a file format for storing digital data,[1][2] defined by an openly published specification usually maintained by a standards organization, and which can be used and implemented by anyone.
Depending on the definition, the specification of an open format may require a fee to access or, very rarely, contain other restrictions.
[5] The range of meanings is similar to that of the term open standard.
[7] The State of Minnesota defines the criteria for open, XML-based file formats as follows:[8] The Commonwealth of Massachusetts "defines open formats as specifications for data file formats that are based on an underlying open standard, developed by an open community, affirmed and maintained by a standards body and are fully documented and publicly available.
Open formats (in the royalty-free and free access sense) include:[5] The following formats are open (royalty-free with a one-time fee on the standard):