Blockchain.info API: How to cancel callback notifications Regarding Blockchain.info's Receive Payments API V2:

The 'Generating a Receiving Address' feature requires a callback_url, to which they send a notification of EVERY confirmation. For every transaction, potentially thousands of notifications will be sent to the callback_url.


When I use the 'Generating a Receiving Address' feature, can I receive a new address WITHOUT specifying a callback_url? 
If I must specify a callback_url:
a. Is there any way to cancel the callbacks?
b. Can I limit the number of notifications that are sent?
1) No

2) your callback url must respond with the text "*ok*" without quotes and nothing else, just text. This will stop Blockchain.info from sending further notifications.