Creating an API Key
Go to https://accounts.useinbox.com and log in to your account.
From the menu on the left, navigate to the API Keys section.
On the screen that appears, click the Add New button in the top right.
Set the expiration date (You can set it 50 years into the future to avoid constant repetition.) and click the Save button in the top right.
And your API key is ready. Copy this API key and save it somewhere.
Entering the API Key into Fonzip
From the menu on the left, navigate to Email & SMS > Settings. Then, go to the Email section at the top and click the Connect to Email Provider button.
On the screen that appears, select Inbox as your email provider, paste the API key you copied into the Inbox API Key section, and click the Save button.
Done! To check if it's correct, go to the Email & SMS menu, then the Mailing Lists section, and you will see your Inbox Marketing mailing lists listed in Fonzip. Similarly, any mailing list you create in Fonzip will also appear in Inbox Marketing.
To transfer desired records to your mailing list in Inbox Marketing, you can use the People & Organizations menu, then Mailing Operations > Add/Remove from Mailing List.