To automatically send your new emails to Customer.io, just follow these steps:

Step 1: Log in to your Customer.io account.

Step 2: Go to your API access tokens by clicking on Settings > Account Settings > API credentials:

You will need both the Tracking API key (to be able to save contacts and attach them to the segments) and an App API key (to get all available manual segments and lookup for existing emails)

Step 3: First click on Tracking API keys > Create Tracking API Key > Enter name (wisepops) > Choose Workspace > Confirm by clicking on "Create Tracking API Key":

Step 4: Copy Site ID and Tracking API Key:

Step 5: Switch to App API Keys > Create App API Key > Enter name (wisepops) > Choose Workspace > Confirm by clicking on "Create App API Key":

Step 6: Store generated App API Key somewhere safe because it will be shown only once:

Step 7 (optional): If you want to control access to your App API, you can whitelist our IP address (34.68.181.17) Add IP Address > Enter IP Address (34.68.181.17) > Choose Workspace > Confirm by clicking on "Add IP Address":

Step 8 (optional): You can subscribe to this list to get notified if we need to add new IPs.

Step 9: Log in to your Wisepops account.

Step 10: Open or create a popup with a sign-up form.

Step 11: Click on your sign-up form.

Step 12: In the left menu, click on Sync, then Customer.io:

Step 13: In the pop-up window, enter your Site ID, Tracking API Key, and App API Key. Uncheck "Use email as identifier" if your Customer.io workspace is not compatible with email identification. Click "Submit".

You're done :)