On last Friday creating a new demo I had the same thought
The current problem in Glide is that the APP/Page must be loaded and running to send data or fire actions. We have to wait a little longer for Glide to get a native solution and let Glide servers (not APPs) send data to external users/apps.
I think you can do it with google sheets or airtable, depend of what function u need, i know with zapier you can do a lot of things, i’m looking for a solution too, no time to do it right now, but i gonna build something similar in the future, it’s about expiration date, like send an email to customer 3 month before the contract gonna expire (no trigger action).
The equivalent solution in Make would be to trigger a scenario to run every day, and have a column in your Google Sheets to calculate the “reminder date” (3 months from the actual expiration date). If “today” is the same as “reminder date” then you trigger the email module.
You should also make sure the dates are formatted in the same way, especially the “today” value, with the formatDate function.