Creates and Sends an SMS or MMS message.
Messages will be sent using the channel that corresponds to the from request parameter. The message body must be less than 1000 characters. Attachment-only messages are also accepted.
If there is no contact corresponding to the to parameter for the organization, a new contact will be created, along with a conversation with the from number channel. If there is an existing contact but no conversation, a new conversation will be created.
The opt_in_to_all_channels and opt_in_to params are optional and they will be processed in the cases where a new contact is created. These params reflect which of the organization channels the contact will be opted in to.
Note: The Messaging API is designed for creating and managing messages and can only process POST requests. To view messages, navigate to the Conversation section where you can use the Show Conversation API to GET messages within a specific conversation.