Double opt-in is a great way to ensure that your contacts are interested in receiving your emails. When you set up double opt-in, your contacts will receive an email asking them to confirm their subscription. Only after they confirm will they be added to the subscribed list.

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Creating an unsubscribed contact

We will start by creating a contact that is unsubscribed. You can do this by triggering an event and setting the subscribed property to false. 
await fetch('https://api.useplunk.com/v1/track', {
    method: "POST",
    headers: {
        "Content-Type": "application/json",
        "Authorization": "Bearer <API_KEY>"
    },
    body: JSON.stringify({
        "event": "subscribed",
        "email": "hello@useplunk.com",
        "subscribed": false
    })
});

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Setting up a double opt-in template & action

Next, we will create a template and action that will be used to send the double opt-in email. For the template there are two possible options:
  • Use Plunk’s subscription page, which is available for each contact at
  • Build your own subscription page and use the contacts API to subscribe the contact.
After you have made your decision, create a transactional template and an action that triggers when the subscribed event is triggered.
It is important to use a transactional template and not a marketing template. Marketing templates will not be sent to unsubscribed contacts.

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Triggering the double opt-in email

Now that everything is set up, you can integrate a trigger for your event into your landing page, blog, or wherever you collect emails. Contacts will remain in an unsubscribed state until they click the link in the double opt-in email and confirm their subscription on the subscription page.