Mailroom Kit live demo

Four of the 14 emails in the kit, built by the real engine from the real templates with sample data for a fictional company. Open any one to see the HTML email as a mail client would draw it (in Chromium here), with the plain-text version beside it. The full kit has all 14, the three placeholder styles, the build, render and check command, 172 tests and the docs.

Reset your password (text version)
The user asked to reset a forgotten password. Subject: Reset your Northfield password
Payment receipt (text version)
A payment succeeded (one-off or subscription renewal). Subject: Your Northfield receipt N-2026-004821
New sign-in alert (text version)
A sign-in from a device or place the account has not used before. Subject: New sign-in to your Northfield account
One-time sign-in code (text version)
Two-step verification or code-based sign-in. Subject: 482 913 is your Northfield sign-in code

What they look like

The receipt email at desktop width: a heading, a table of receipt number, date, plan, period, amount, tax and total paid, a blue button to view the invoice, and a footer with the support address — Receipt, light, 640 px wide.

The new sign-in alert email on a phone in dark mode: device, location and time, then a Secure my account button — New sign-in alert, dark mode, 375 px wide.

The checker's verdict on these four

Output of node mailroom.mjs check --rendered on the four filled emails, unedited:

ok   login-code.html              6.3 KB, 1 links, 0 errors, 0 warnings
ok   new-login-alert.html         8.3 KB, 3 links, 0 errors, 0 warnings
ok   password-reset.html          6.7 KB, 3 links, 0 errors, 0 warnings
ok   receipt.html                 10.3 KB, 3 links, 0 errors, 0 warnings

4 files, 0 errors, 0 warnings. This measures the files; it does not render them in Outlook, Gmail or Apple Mail.

The checker measures the files. These emails were looked at in Chromium only, not in Outlook, Gmail or Apple Mail. Check your own email's HTML for free.