mail-preview

A zero-config dev-mode mail preview UI for Meteor. Every email sent via Email.sendAsync() is captured and displayed in a browser UI at /__meteor_mail__/.

Inspired by similar features in Rails (Action Mailer Preview), Phoenix (Swoosh), Laravel (Mailtrap), and Django (console backend).

Installation

meteor add dupontbertrand:mail-preview

That's it. No configuration needed.

This is a debugOnly package: it is left out of production builds (meteor build, meteor deploy, meteor run --production). Zero overhead in production, no need to remove it before deploying.

Usage

1. Start your Meteor app in development mode (meteor run)
2. Trigger any email (e.g. password reset, verification, etc.)
3. Open http://localhost:3000/meteor_mail/ in your browser

What you get

• Mail list — live-updating table of all captured emails (polls every 2s, no page reload)
• Mail detail — view each email with tabs for HTML render, plain text, and HTML source
• Clickable links — verification, password reset, and enrollment links work directly from the preview
• JSON API — programmatic access for testing/tooling
• Clear all — one-click button to clear captured mails

JSON API

Method	Endpoint	Description
GET	/__meteor_mail__/api/mails	List all captured mails
GET	/__meteor_mail__/api/mails/:id	Get a single mail
DELETE	/__meteor_mail__/api/mails	Clear all captured mails

How it works

The package uses Email.hookSend() to intercept outgoing emails and store them in memory. A middleware serves the preview UI via WebApp.rawConnectHandlers.

• Dev mode only — the package is left out of production builds (debugOnly: true), and its code is a no-op outside development (Meteor.isDevelopment guard)
• No SMTP needed — emails are captured before they reach any transport
• No dependencies — uses only Meteor core packages (email, webapp, ecmascript)
• Up to 50 mails stored in memory (oldest are evicted)

Compatibility

• Meteor 3.4+
• Works alongside MAIL_URL — emails are still sent normally, the hook just captures a copy
• Works with accounts-password emails (verification, reset password, enrollment)

Changelog

1.2.1

The package is now debugOnly instead of devOnly. Since Meteor 3.4, and at least up to 3.6-rc.0, devOnly is not applied to a package whose name has an author prefix, so versions 1.2.0 and earlier were still shipped in production builds. They stayed inert there, thanks to their Meteor.isDevelopment guard; upgrading removes them from the bundle.

License

MIT