If you haven't already, you'll need to sign up for an ActiveCampaign account.
Setting up your ActiveCampaign API key
Navigate to the Developer screen, by clicking the settings icon next to your profile picture. Next, click 'Developer' in the settings menu.
Paste in the API Key and URL on your settings page under "Integrations"
You're all set!
💡 Tip: You can now head to the opt-in form support article to add/complete your opt-in form.
Setting up double opt-in
If you're looking to be GDPR compliant, you'll need to set up a double opt-in workflow. In ActiveCampaign, you'll set up an automation workflow that sends a double opt-in confirmation email to a new contact based on a tag being added. Check out ActiveCampaign's support article for more help getting the workflow setup.
When setting up your Opt-in form, just select the "Tag" type: