My chrome extension users can set reminders to track changes to an HTML page. I track those pages on a server-side web crawler. If there exists any new changes, I create a notification entry in a table.

Now the user needs to be notified about this notification. I am confused about how would I do it in a chrome extension.

I thought about writing a CRON job that checks for updates every 30 mins. But will that be a bad decision? will it put too much load on a client side?