MailOptin offers a seamless integration with Moosend email marketing service.
Go to the Integrations settings page by either clicking the sidebar menu link or top menu tabs.
At the Moosend Connection section, you will see a text field to enter your API key.
To get your API key, login to your Moosend account and navigate to Account >> API Key
Copy your API key, paste it in the “Enter API Key” text field and finally click the “Save Changes” button to save.