as most of the european-based companies can’t use mailchimp due to GDPR requirements, a prominent alternative is mailerlite. I’m using this myself and I was looking for a tutorial / plug-in to integrate it in my bubble application.
I wasn’t very lucky, so I created my very first plug-in (yeah ;:)) myself.
Now you can show subscribers, groups from mailerlite in your application. The most common used feature however is that you can add subscribers from your application to mailerlite without any additional 3rd party service.
Here you can find the plug-in page: Mailerlite Plugin | Bubble
Here, you can find some instructions: How to integrate mailerlite into your bubble.io application - Biberei
This is the very first try, if you have feedback please tell me so that I can improve
Many greetings from Germany.