How to keep track of new entries on the web page and get notified when they appear?

Question

API

Here is a page on the site: https://upbit.com/service_center/notice
Here is this page in JSON: https://api-manager.upbit.com/api/v1/notices?page=...
How can I monitor the appearance of new posts and receive instant notifications about it?
Maybe there is a special service for this? Notifications are needed immediately, preferably without delay at all.

Answer 1

If I understand correctly and the API is not yours, then instantly and without delay in any way.
In this case, you need to use Long Polling, i.e. constantly make periodic requests through, for example, CRON and compare the result with a snapshot. Next, update if there is new data.

Answer 2

Parse the page every second and check the data until you get banned.
There is no other way.

Answer 3

the date of the update is indicated, parse and check, the headers there are generated, incl. you can't check them