You can also use these Mailchimp merge tags in your Transactional Email emails:
*|FNAME|*
*|LNAME|*
*|EMAIL|*
*|DATE:FORMAT|*
*|CURRENT_YEAR|*
For *|FNAME|* and *|LNAME|*, Transactional Email will try to parse the name in the To header of the message to get the recipient's name. For *|EMAIL|*, we'll look at the recipient's email address in the To header to populate the value for that tag.
Use *|DATE:FORMAT|* to show the current date in a specific format. For example, *|DATE:d/m/y|* where d is replaced by the day of the month in 2 digits, m by the month with 2 digits, and y by the year in 4 digits. View a full reference of date options on http://us3.php.net/manual/en/function.date.php.
Most other Mailchimp merge tags won't work by default in Transactional Email. Tags like *|ARCHIVE|*, *|LIST:ADDRESS|*, integration-specific tags, and RSS-to-email merge tags have a specific meaning in Mailchimp as they're tied to a list or campaign.
Transactional Email does not store lists or campaign data, so you can use merge tags to personalize emails in Transactional Email, but you also need to provide the values for those merge tags at the time of send in your API request or SMTP message.
Create an Online Version of Your Emails
The Mailchimp *|ARCHIVE|* merge tag creates an online version of your email so recipients can view it as a webpage in browsers. Most transactional emails are highly personalized or contain information that should not be publicly-accessible, so Transactional Email doesn't create a public version of those emails. You might consider hosting a version of the email on your own website that you can link to in your emails.
Track forwarded emails
The Mailchimp *|FORWARD|* merge tag generates a link to an online form where recipients can share your email with others. Because Transactional Email emails are generated and tracked individually, a web version is not automatically provided.
To mimic the Forward to a Friend option in Transactional Email, you could create your own online version of the email, host it on your website, and then give your recipients a way to share that online version with friends (through a direct link or an online form). Then you could track when people fill out the form or when they click the link for the shared email.
Unsubscribe from Transactional Email emails
Transactional Email provides an easy-to-use merge tag to add an unsubscribe link in your Transactional Email emails automatically. Transactional Email's *|UNSUB|* merge tag uses a similar format to the Mailchimp unsubscribe merge tag: it consists of the word UNSUB, followed by a colon, and a full web address (with http:// or https://) where recipients should be redirected when the unsubscribe is processed:
*|UNSUB:http://mywebsite.com/unsub|*
You can also provide a link to your own unsubscribe process.