Using mail.tm instead of your own domain

This is the low-setup option: no domain, no DNS, no server that needs to receive inbound mail. Addresses live on mail.tm's own domain instead of one you own. Discord setup is still a separate step in discord-adapter.md, same as every other path.

Read this before picking it: addresses on mail.tm's domain are recognizable as a public disposable-mail service, and a meaningful number of signup forms specifically detect and block known temp-mail domains including mail.tm. A chunk of the reason to run your own domain in the first place is that it doesn't look disposable to anything. This path trades that away for zero setup. If a given site rejects the address, that's what's happening, not a bug here.

What you need

• Node.js 18 or newer, or Docker.
• A Discord application with a bot.
• Nothing else. No domain, no DNS, no port 25.

You do still need one thing every other path also needs: a public HTTPS URL for Discord's interactions webhook. See step 3 below, it's the same requirement as the self-hosted path for the same reason.

npm run setup does steps 1 through 3 below interactively if you'd rather not do them by hand. The rest of this guide is what it's doing on your behalf, and what to do once it's finished.

1. Clone and install

git clone https://github.com/Psalm2517/Cindermail.git
cd Cindermail
npm install

2. Configure

cp .env.example .env

Fill in the three DISCORD_* fields (see discord-adapter.md for where to get them). Leave DISPOSABLE_DOMAIN out entirely, this mode doesn't use it. See configuration.md for the rest.

3. Run

npm run start:mailtm

This creates a local SQLite file (same as the self-hosted path) and starts polling mail.tm every 15 seconds by default (MAILTM_POLL_INTERVAL_SECONDS). No SMTP server, no inbound port at all, since mail.tm handles receiving on their infrastructure and this just checks in periodically.

You should see:

Cindermail (mail.tm mode) starting. storage: ./cinderbox.db
Interactions HTTP server listening on :8787 (POST /interactions)

4. Get the webhook onto HTTPS

Same requirement, same reasoning as the self-hosted path: the bundled HTTP server is plain HTTP, Discord needs HTTPS. Put a reverse proxy (Caddy, nginx) or a tunnel (Cloudflare Tunnel, ngrok) in front of HTTP_PORT. See deploy-selfhost.md for the same section written out in more detail, it applies here unchanged.

Then finish the rest of discord-adapter.md: register the commands, point Discord's Interactions Endpoint URL at your HTTPS URL, done.

How addresses work here

/new calls mail.tm's API to actually provision a mailbox on their side (not just generate a name on a domain you own), and stores the password needed to poll it. /torch and expiry both trigger deleting the account on mail.tm's side too during the daily cleanup, not just the local row, so nothing lingers on their servers past its grace period.

Running with Docker

The same Dockerfile works, just override the command and drop the SMTP port mapping since nothing listens on it in this mode:

docker build -t cinderbox .
docker run -d \
  --name cinderbox-mailtm \
  --restart unless-stopped \
  --env-file .env \
  -p 8787:8787 \
  -v cinderbox-data:/data \
  cinderbox \
  node --experimental-strip-types src/receivers/mailtm/run.ts