Have you ever done work with any subscription apps to enable subscription based loyalty, or have API endpoints that could offer this?

We have, it worked by creating Shopify orders automatically each month, which were in turn sent to us via web-hooks and we triggered our rules on them as needed.

That said, all our functionality can be triggered via our API too, so a subscription could be triggered by adding an order to LL, or triggering a custom activity each time the subscription renewed.

If you have any further questions please email: support@loyaltylion.com