Beehiiv New Subscriber Agent

Most newsletters learn who their readers are months late, from a spreadsheet somebody exported. This agent tags each new subscriber the minute they land, with the source, the referrer and the tier they arrived on, and fills the custom fields you build segments from while that context still exists. The team hears about the signups that matter, a domain you sell to or a paid annual, and never about the other four hundred.

What people use it for

• See which swap actually works - Source and referrer become tags on the day someone subscribes, so a partner send is measurable inside beehiiv rather than reconstructed later out of link data.
• Notice a reader worth an email - A signup on a domain you sell to reaches Slack with its tier and source attached, so somebody can send a real note that morning instead of finding them in a quarterly export.
• Paid signups get a moment - Every upgrade and annual plan shows up in the channel as one line. Small teams read that as the scoreboard, and it costs nothing to keep running.
• Segments that build themselves - Custom fields get filled while the signup context is still there, so the segment you want in three months is already populated when you go looking for it.

Before you fork

What does it need before the first subscriber?

A beehiiv API key for the publication, plus whichever Slack channel notable signups belong in. Then you write the tagging rules: which tags come from source, referrer and tier, which custom fields you want filled, and what counts as notable. Everything else it needs is already sitting in the subscription record.

Will it turn Slack into a signup feed?

Only if you write the rules that way. Its default posture is silence, because tagging is the real work and pinging is the exception. Most publications settle at a handful of lines a week out of hundreds of signups, and if the volume feels wrong you tighten the notable rule rather than the agent.

Can it touch subscriptions or send anything?

No on both counts. It has no send tool, so no reader ever hears from it, and it cannot change a status, move a tier or remove anyone from the list. It applies tags and writes the custom fields your rules name, both of which you can undo in beehiiv yourself. Billing and the subscription record stay outside its reach.