Anyone receiving commercial communication can ask to stop at any time. The request must be honoured immediately, free of charge and without conditions — no reason form, no "are you sure", no automatic reactivation six months later.
What "immediately" means
In practice: from the moment the request is recorded, no new commercial message goes to that number. If you have a campaign already queued, opt-out must be checked at send time, not at list-building time.
This is where integrations most often fail: the list is generated Monday morning, the campaign goes out Wednesday, and Tuesday's request is never considered.
Opt-out does not stop transactional messages
Unsubscribing concerns commercial communication. A customer who opted out of marketing still receives the OTP code for signing in, the order confirmation and the delivery notification — because those messages follow from the contract between you, not from marketing consent.
If you block all traffic to an unsubscribed number, you break your own functional flows. Keep the two regimes separate in your database.
How to implement it
Calisero exposes a dedicated endpoint for opt-out lists. The minimum working flow:
- Record the request the moment you receive it, whatever the channel — reply SMS, email, web form, a call to support.
- Check the list before every commercial send, not when building the segment.
- Keep the record permanently. Deleting it would mean messaging the same person again a year later.
- Log the time and source of the request — the burden of proof is yours.
What you keep, and for how long
The minimisation principle requires keeping only what you need, for only as long as you need it. For transactional messages, a reasonable retention period covers support and financial reconciliation needs; after that, the content has no reason to exist.
The opt-out list is the exception: it must be kept precisely so you can honour a request that never expires.
Document the consent
When you rely on consent, you must be able to show when it was given, how and for what. A pre-ticked box is not consent. An order form that hides marketing agreement among the terms is not freely given consent.
A simple register — timestamp, IP address, the exact text shown at the moment of agreement — covers the requirement and settles any later discussion.
