FAPI.UI.showNotification and notifications.sendSimple, what are the differences? How exactly does notifications.sendMass work?

Question

Classmates

Hello!
I was looking through the Odnoklassniki API and came across two methods: FAPI.UI.showNotification and notifications.sendSimple. Both methods are for sending alerts to other users. Of the obvious ones, I singled out the following differences:
Recipients: the first has up to 20 already selected, the second has exactly one.
Limit: the first has up to 20 calls, the second has up to 5 calls.
Are there any other differences between these methods? Which one is better to use? Isn't the notifications.sendSimple call hidden under FAPI.UI.showNotification?
Now about notifications.sendMass. I don't fully understand how this thing works. Is it some kind of sticky alert for users?
And the last question.
Is there any mechanism to check for alerts and get those alerts using the API?
Facebook implemented this using GameRequests, and when I enter the game, I only need to request a list of requests and then do whatever I need with them.

Answer 1

FAPI.UI.showNotification - this is a notification from a user to another user
notifications.sendSimple - a notification from the game to a user
The limit of FAPI.UI.showNotification is calculated for each user separately, he can send no more than N notifications per unit of time to other users.
notifications.sendSimple is limited so that the application cannot send more than N notifications to the same user in a unit of time
notifications.sendMass is almost like notifications.sendSimple, but it is sent not to one user, but to the whole group of application users. The group of recipient users is determined using the remaining parameters of the method. And visually, these alerts are the same.
We do not have a tool to check for availability and receive notifications by the game. Our services do this, they also show these game notifications in special blocks (in the web version of the portal, in the mobile version, in applications for Android and iOS)