beehiiv

Build me a personal newsletter system to replace beehiiv. Requirements: - Node + Express + better-sqlite3. Posts are Markdown files in posts/; subscribers live in SQLite: email, token, subscribed_at, unsubscribed_at. - A localhost admin page: write and preview a post (marked, rendered inside a tested single-column email HTML template), see subscriber count, send. - Sending via Resend or plain SMTP, creds in .env. Every email carries a one-click unsubscribe link (token in the URL) and a List-Unsubscribe header; that is a legal requirement, never skip it. - Log each send per subscriber as sent or failed so an interrupted batch resumes without double-sending anyone. - Public surface, deployable as one small server: a subscribe form with a double-opt-in confirmation email, and a web archive of past posts at /archive. - CSV import and export of the subscriber list. - Out of scope: open/click analytics, referral programs, and paid subscriptions; beehiiv's growth network is the actual product. - README: .env keys, the ESP's SPF/DKIM DNS records, and a blunt warning to warm up a new sending domain slowly or everything lands in spam; deliverability is most of what the fee buys.