I'm looking for a very simple SMS gateway with the following features:
Various buttons (about 6) on the screen (images provided), when clicked send pre-programmed SMS messages
The SMS messages are sent to a phone number stored in a MySQL database, which is associated with the customer that is logged in to the site (using pre-existing OpenCart system)
Page can only be accessed by users who are signed in
SMS gateway key must be hidden from the user so that they can't find it and use it for their own messaging to other numbers and for other purposes.
I would prefer one of the free SMS gateways available, but speed of the commands is an important factor, so if a free gateway will cause a lot of lag time, I would rather pay a monthly fee, since there seem to be many cheap services out there.
If this is something you or your team can do, I look forward to hearing from you.