Although they claim so on this page https://developer.metrobankonline.co.uk/, at the moment Metro Bank PLC is simply not adhering to Open Banking specifications.
This is clearly shown under their listing in the Open Banking transparency ledger.
Being compatible with Open Banking is now mandatory and regulated under the FCA.
This is why all major open banking providers do not support Metro Bank.
We believe it that they will eventually be forced to adhere to the specifications and are continually checking on their progress.
Once they comply with the rules we immediately work to integrate with them along with all other UK banks.