I can easily assure you that using ABC music notation would be far easier to implement than to continue using MusicXML. The syntax for ABC music notation is in plain text and is the lingua franca for traditional Irish & Celtic tunes. Please reconsider building your API with MusicXML. Music notation is not a format, it is a language, and should be interpreted as such.
Thank you for contacting us.
Indeed, at present our solution only supports the MusicXMl format. Your request has been forwarded internally, and may be considered in a future release.