Every subscriber in Buttondown carries a source — a little tag for where they came from, whether that's an embedded form on your site, a Stripe checkout, a Patreon import, a Zapier zap, or just you typing their email in by hand. We've shown that information on the subscriber page for ages, but until now it's been read-only.

Well, it's still read-only — but now it's a lot more useful. Starting today, source is a proper filter you can use in two places:

• Audiences. When you're building a custom audience, you can now narrow on source the same way you'd narrow on tags or open rates. Want to send a thank-you to everyone who came in through your Stripe checkout last month? Filter on source contains stripe and go.
• Automations. The same filter is available inside the new automations builder, so you can branch behavior based on how someone signed up. A welcome series can send one variant for organic signups and another for folks imported from Patreon, all from a single trigger.

A few practical examples newsletter authors have asked us about:

• Tag everyone who signed up via your embedded form so you can tell them apart from API-created subscribers down the line.
• Send a survey only to subscribers who came in organically (i.e. through your subscribe page), where the conversion intent is strongest.
• Skip the welcome email entirely for imported subscribers, since they've already heard from you somewhere else.

This is live for everyone, on every plan, with no setup on your end — your subscribers' sources have been recorded all along.