Buttondown is a deliberately small newsletter tool: write in Markdown, send to subscribers, see simple analytics. It stays out of your way — no drag-and-drop builder, no marketing suite — and layers on the things writers actually ask for, like paid subscriptions, RSS-to-email and a clean API.
It suits writers who want publishing without a growth platform attached. If you are building a media business with referral programs and monetization tooling, beehiiv is the better fit; if you want deeper automations, Kit covers more.