In most countries, it's a requirement to allow contacts to opt-out of marketing SMS messages. If your contact changes their mind, they can opt back in.
Premium rate numbers
Some service providers or mobile devices see short codes as premium rate numbers. If a contact tries to send an opt-out SMS message and they have a network block for premium numbers, the opt-out won’t work. This appears as not sent for the contact who's trying to opt-out.
For Android users, they might see a message that says This may cause charges to your mobile account when sending SMS messages to five digit numbers.
Opt-out with a shared short code
To unsubscribe with a shared short code, contacts can reply or send an SMS to your short code with the keyword, followed by a space, followed by a designated word, such as STOP.
Learn more in the section Opt-out words.
For example, if your keyword is COMPANY, a contact needs to send COMPANY STOP to your short code to opt-out.
Your contacts are only opted out if the opt-out word follows directly after the space and after the keyword, that is KEYWORD OPTOUTWORD.
For example, if the keyword is COMPANY, your contact needs to be instructed to reply with COMPANY STOP. If any other characters are added before the opt-out word then the opt-out won’t work.
Opt-out with a long number
A long number is dedicated to your company, so you don't need a keyword to allow contacts to unsubscribe from your SMS campaigns.
To opt-out with a long number, contacts must send an SMS message to your long number with an opt-out word. The opt-out word must be the first word in the response from the contact for the opt-out to work.
SMS click to unsubscribe
Instead of contacts having to send an SMS message to you in order to unsubscribe, in certain regions it’s possible to allow them to unsubscribe simply by clicking a personalised link in a message you have sent to them.
Learn more in Use SMS click to unsubscribe.
Opt-out through a signup form
You can create a customised unsubscribe form to allow contacts to opt-out of your SMS marketing.
Learn more in Use a customised unsubscribe form.
Opt-out words
STOP is the most common opt-out word, but there are six possible opt-out options:
CANCEL
END
QUIT
REMOVE
STOP
UNSUBSCRIBE
Opt back in with a shared short code
To resubscribe to your SMS campaigns with a shared short code:
Your contact can reply to an older SMS campaign you sent before they opted-out.
The contact can send a new SMS message to your shared short code with the keyword, followed by a space, followed by either the word START or UNSTOP.
For example, if your keyword is COMPANY, a contact must send COMPANY START or COMPANY UNSTOP to opt back into your SMS campaigns.
Opt back in with a long number
Since a long number is dedicated to your company, you don't need a keyword for contacts to opt back in.
To resubscribe to your SMS campaigns with a long number, your contact can reply to an older SMS campaign you sent before they opted-out.