Email

Tack sends one kind of email: weekly digests, and the confirmation that comes first. It’s off until you set it up, and everything else works without it: boards can still post their digests as GitHub Discussions.

Email goes out through Cloudflare Email Service, from a domain on your Cloudflare account.

Setting it up

1. In the Cloudflare dashboard, open Email Service and onboard a domain for sending, on the same account as Tack. Cloudflare adds the DNS records sending needs (SPF and DKIM). Use a subdomain, like mail.example.com, if your main domain already sends mail from elsewhere.

2. In your copy of Tack, set EMAIL_FROM at the top of cloudflare.config.ts to the address digests come from, on that domain:

   const EMAIL_FROM = "Tack <tack@mail.example.com>";

   This also adds the send_email binding (TACK_EMAIL) that sends it.

3. Run pnpm run wrangler-config, commit, and deploy.

Then Weekly digest… on a board offers Email people who ask for it. Until then, it says “This Tack can’t send email yet”.

What it sends

• A confirmation, when someone asks for a board’s digest from the board: a link to confirm the address, good for a week. Nothing else goes until it’s followed. Someone can ask again after ten minutes, a board sends at most twenty an hour, and at most 200 people get each board’s digest.
• The digest, once a week, as HTML and plain text, with no images or tracking. Each has a link to stop and the List-Unsubscribe headers mail apps use for their own unsubscribe button.

Only people allowed on the instance can ask, and only for boards they can open. An address that bounced or complained before (suppressed by Email Service) is unsubscribed.

When it doesn’t go

Recent digests in the board’s dialog, and the logs (digest.email.failed, with Email Service’s code), say why:

Code	What to do
E_SENDER_NOT_VERIFIED	EMAIL_FROM isn’t on the domain you onboarded
E_SENDER_DOMAIN_NOT_AVAILABLE	The domain isn’t onboarded for sending yet, or its DNS records aren’t in place
E_RATE_LIMIT_EXCEEDED	Sending too fast: Tack tries again in 15 minutes
E_DAILY_LIMIT_EXCEEDED	The account’s daily limit is used up: Tack tries again later
E_RECIPIENT_SUPPRESSED	The address bounced or complained before: they’re unsubscribed, and can ask again

Local development

The dev server always has email on, from tack@example.com. Nothing leaves your machine.