We recommend that you always include a MailUp unsubscribe link in any message sent via MailUp (unless the message does not require an unsubscribe, which is very rare).

In some cases, however, some MailUp users elect to use an unsubscribe link that points to a different system (e.g. an internal CRM), or not to include an unsubscribe link and provide the recipient with different unsubscribe instructions (e.g. "Reply to the message with...").

In that scenario:

the must unsubscribe preference is passed to MailUp as soon as possible
There are many ways to do so, and they are listed here
A risky alternative is not to update the MailUp system with the unsubscribe preference (not recommended!!), and instead do the following:
- Import the unsubscribed recipients into a dedicated Group right before sending the next campaign
- Exclude that Group when choosing recipients for the campaign
- In this setup, the Group works as a suppression list for that campaign

Don't compromise your sender reputation

We strongly recommend - and in many cases require - that you use the unsubscribe links built into the MailUp system: you can fully customize them in terms of location and look. Using an external unsubscribe procedure exposes you to the risk of not having updated unsubscribe information in your list, which could lead to higher spam complaints, lower sender reputation, and possible account termination. Do not take these risks.