Application-defined data attached to this order. Metadata fields are intended
to store descriptive references or associations with an entity in another system or store brief
information about the object. Square does not process this field; it only stores and returns it
in relevant API calls. Do not use metadata to store any sensitive information (such as personally
identifiable information or card details).
Keys written by applications must be 60 characters or less and must be in the character set
[a-zA-Z0-9_-]. Entries can also include metadata generated by Square. These keys are prefixed
with a namespace, separated from the key with a ':' character.
Values have a maximum length of 255 characters.
An application can have up to 10 entries per metadata field.
Entries written by applications are private and can only be read or modified by the same
For more information, see Metadata.