Paythen does not currently have an API. We do have a Zapier app in with detailed and granular triggers as well as an action that allows you to trigger custom payment plan links to be sent via email with data from almost any app (like your CRM, google sheets, and more). You can see more details about our Zapier app here.
Alternatively, you can also achieve many advanced workflows by directly using the Stripe API which is comprehensive and well documented. When Paythen creates a customer, subscription or payment in your Stripe account, we provide comprehensive and structured metadata with unique plan and customer identifiers in your Stripe account record so any direct Stripe integration will also be able to access key Paythen data easily.
If you'd like to be kept in the loop about this if and when we have updates, let us know via the chat icon.