Push notification from user A to user B

Hi, i want to push notification from user A to user B.
Eg: in link https://mywebsite.com/itemid: user A comment and @mention user B.
User B will receive notification and click this notification will jum to link item https://mywebsite.com/itemid
How can i do it? Thank you

You can achieve this by
1- Storing Subscriber ID on your server for each user. API Guide: How to Fetch Subscriber ID - Webpushr
2- Sending custom push to an individual user using this API endpoint: API Guide: Send Push Notification to a Subscriber ID - Webpushr