Metadata are useful for search or organization purposes. You can add metadata to your transaction as key-value pairs (if the value is missing, the key will be ignored). You can add a maximum of 15 metadata per transaction. Each metadata key is limited to 20 characters, while the value is limited to 200 characters. Metadata are for internal purposes and are not displayed to the participant.
Important: the use of the equal sign (=), plus sign (+) and underscore (_) are not supported in the metadata key. Brackets ([]) are allowed only in opening and closing pairs otherwise they are ignored.
