Is FileMaker WebDirect supported?

Yes - fmSMS supports FileMaker WebDirect (fmSMS will need to be hosted with FileMaker Server v16 or later to use WebDirect). 

When you open fmSMS with FileMaker WebDirect you will navigate to specific layouts for the web browser access. We’ve added support for viewing Contacts and sending Messages with FileMaker WebDirect – additional support can be easily added as required, for example to view Replies, Delivery Receipts or send a bulk SMS to a found set of Contacts. As fmSMS is completely unlocked you can also create additional layouts or modify these example layouts as required.