Install MailDev

Run MailDev with npx, install it globally with npm, or pull the Docker image. Node.js 20 or newer is the only requirement.

Run it without installing

The fastest way to get an inbox. Nothing is added to your project or your global node_modules:

npx maildev

MailDev prints the two addresses it is listening on and stays in the foreground:

MailDev webapp running at http://0.0.0.0:1080
MailDev SMTP Server running at 0.0.0.0:1025

Open http://localhost:1080 and leave it running while you work.

If you reach for MailDev often, a global install saves the download on every run:

npm install -g maildev
maildev

No Node.js toolchain required:

docker run -p 1080:1080 -p 1025:1025 maildev/maildev

See the Docker guide for Compose, environment variables, and the image's health check.

Adding MailDev to the project that needs it keeps the version pinned in your lockfile, which matters most in CI:

npm install --save-dev maildev

Then wire it into a script:

{
  "scripts": {
    "dev:mail": "maildev",
    "dev": "concurrently \"npm:dev:*\""
  }
}

You can also start and stop it from Node.js directly, which is usually the better shape for integration tests.

Ports 1025 and 1080 need to be free. Both are configurable — see --smtp and --web if something else already owns them.

maildev --version

And once it is running, the API's health endpoint answers without authentication:

curl http://localhost:1080/api/healthz

MailDev 3.0 is a complete TypeScript rewrite: React web UI, Fastify API, and the new MCP server. If you are upgrading from 2.x, the CLI flags are unchanged but the programmatic API moved from callbacks to promises — the full checklist is in Upgrading from 2.x to 3.0.

Hit a regression in 3.0? The 2.x line is still available — npm install -g maildev@2 — and a report on the issue tracker is genuinely useful.

Point an application at it: Quick start.