Keyword Set-up
10DLC
For 10-digit Long Code (10DLC) numbers you can specify keywords to be used, as well as text to be used in message replies. This can be done either via the Developer Dashboard, or via the 10DLC API.
Developer Dashboard
Setting up keywords and reply messages can be done as part of the campaign set up process. As part of this process, you can specify custom keywords for Opt-in, Opt-out, and Help messages, as well as sample message reply text for all three types of message.

10DLC API
The 10DLC API can be used to manage various aspects of 10DLC Brand and Campaign Provisioning, including keyword set-up for Opt-Out Assist.
The following fields can be set via the API:
opt_in_keywordsopt_out_keywordshelp_keywordsopt_in_messageopt_out_messagehelp_message
The fields can be set via a couple of endpoints.
You can also get the current value of these fields, as well as checking whether Opt-Out Assist is enabled for a campaign (via the opt_out_assist field), via the following endpoints:
Short Codes
For short codes, the following keywords are mandatory as part of the short code registration process (it is not possible to set custom keywords):
- Opt-out:
STOP,END,QUIT,CANCEL,UNSUBSCRIBE - Opt-in:
START,JOIN - Help:
HELP