Webhook for Notification Events that includes a total?

I am currently using the API to get the number of notifications on my forum to display on my sister website, but even caching this for 60 seconds requires 1 API request per user per minute, which will not scale well.

Ideally I’d like to use a webhook, so every time the user gets a notification it sends the data to my sister website, which stores the number. Then when the user clears their notifications, it also gets cleared.

But there does not seem to be a way to create a webhook event for clearing notifications? Is there any way to add this?

Or, even simpler, add to the current notification webhook a number of the total unread notifications, so every time someone gets a new one I can update the database to include that.

This would really help keep my websites in sync and prevent an upcoming API limit nightmare. Please help!

(Also, if there is a way to get Chat notifications via webhook or API, I really would like to know!)