This article discussed how you can use Sendy's Unsubscribe API to unsubscribe a customer.
The unsubscribe API requires the fllowing
You will need the following
Then API end point is https://your_sendy_installation/unsubscribe
Once you make the call, in the response, you will see HTML saying "You have been unsubscribed".
Here's an example curl command for this
curl -X POST https://<your-installation>/unsubscribe -d 'email=support@sendybay.com&list=<your-list-id>
In the above, you will need to replace <your-installation> and <your-list-id> with correct values.