SD SMS Master is an SMS-sending server. The Web server (master) contains the SMS Master itself. Clients (users) connect to the master and create orders. Orders contain a text to send and a list of numbers to send to. The master then connects to remote machines (slaves) and distributes the order numbers (+text) to all enabled phones on the slaves. The communication is one-way; incoming SMSes are not read.
Textlocal API2 Wrapper is a PHP class that can send SMS or MMS messages using the Textlocal API over HTTP. It can send an SMS or MMS message to a given number, send a message to a group of contacts, create groups of contacts, add contacts to a group, retrieve the available groups, delete contacts from a group, delete groups, retrieve message history, etc.