Buttondown's templating language supports conditional logic in both subject lines and email bodies. This lets you personalize content per-subscriber based on their metadata — for example, sending different copy to cast members vs. regular viewers.
For example, if you need different subject lines based on a metadata flag:
Subject line:
Email body:
This is evaluated per-subscriber at send time, so each recipient sees the version that matches their metadata. You can use any metadata key in these conditions, and you can nest multiple conditions for more complex logic. This works in both regular emails and automation emails.