With this solution you can improve inter-operability with your CRMs, Apps, and ERP systems with SMS.to by automatically adding or removing customers from your account recipient list (opt-in & opt-out)

In a nutshell you can easily use our opt-out links without the need to first actively create any contact lists on SMS.to and have greater control over un-subscriptions and re-subscriptions.

To unsubscribe a recipient, you can do following:

Add "STOPSMS {optout}" - without the double quotes - in the message content. 

It could also be "unsubscribe here: {optout}" or " NOSMS {optout}". The important part is the placeholder, which will be converted into a link during send automatically. It is best practice to use a keyword like STOPSMS because otherwise recipients might take it for a promotional link and click it without the real intention to un-subscribe. The wish to un-subscribe will have to be confirmed once more by clicking a button on the linked page to prevent accidental clicks.

At this point, the recipient will be globally un-subscribed on the respective SMS.to account while remaining in the list of contacts. If the associated phone number was not yet in the list of contacts on your account, it will be created on-the-fly to allow un-/resubscription.

On the next sending, the recipient will be skipped, and no charges will be made. Please also refer to Opt-out & Opt-in: subscribe or un-subscribe contacts for more information.

The following endpoints can also be called manually if required so that you can opt-in and opt-out contacts on demand giving you full control over your recipients and their status:

https://docs.sms.to/api/#optin-contacts

https://docs.sms.to/api/#optout-contacts