Optingun Integration with MailChimp
Integrating your Optingun forms with MailChimp is super easy, its takes only 3 steps to finish the whole process.
Go to your MailChimp dashboard, and click on profile name on top menu and then click "Profile" from the popup menu

From this Page, click on Extras > API Keys

Now copy the API Key from this page
Now in the admin area of Optingun, click on top hanburger icon to reveal menu, and click on "API configuration" from there, or click on "Connect your Apps" button from dashboard home page, you will land on API configuration page

This page will list all the Apps, now click on MailChimp icon, this action will display API Key and Secret Key fields, you need to put your MailChimp keys here and save the settings, make sure you are entering the key with out any extra characters or spaces
Go to your forms or create new form, and navigate to Integrations tab using the left side menu, and from email software selector, select MailChimp, this will connect to MailChimp in real-time and load all the contact lists that are available there, select the list that you want to add contacts to and click on "Add Integration" button, now you should see the rule description on right side tab, after this, update your form by clicking the green button on left side menu as shown in the picture below with numbering.
This is all you need to do to connect your forms with MailChimp, enjoy using it.