Hi Niko,
Sorry for the inconvenience caused.
For your kind information, we can load remote data source to the TreeGrid control using ejDataManager with the help url in Javascript. Currently there is no support to update the changes to the remote Data Source using remoteSaveAdaptor/ UrlAdaptor.
Hence we have also logged a feature regarding this. A support incident has been created under your account to track the status of this requirement. Please log on to our support website to check for further updates.
https://www.syncfusion.com/account/login?ReturnUrl=/support/directtrac/incidents
Please let us know if you require further assistance on this.
Regards,
Mahalakshmi K.