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MailDev MCP Server: Setup for Claude, Cursor and Other Apps

OfficialLocal
Getnpm@maildev/mcpmaildev/maildev/tree/HEAD/packages/mcp
Tools
5
4 read · 1 change
Downloads
6.3K
a week
Works in
12
apps
Risk
High
can delete
Auth
None

Lets Claude or Cursor search and read the test emails your app sends to MailDev, and delete them when you are done.

This is the MailDev project's own MCP server. It lets Claude, Cursor and other assistants search the emails caught by a MailDev inbox, open one with its attachments, and delete it.

It runs on your computer and talks to the MailDev web server, which it expects at http://localhost:1080 unless you point it elsewhere. You need MailDev running first. The package README also says the same server is built into the MailDev API server, so you may not need the separate package if you already run that.

Good for

  • Developers who test signup, reset and receipt emails with MailDev
  • QA engineers who want an assistant to check what a test run sent
  • Anyone who wants Claude to pull a verification link out of a test inbox

Works in

12 should work

Tap an app to see how to set it up and any known problems.

Install MailDev MCP

Claude Code

  1. 1

    Copy this prompt.

    Add the MailDev MCP server to Claude Code. Run this command:

claude mcp add maildev -- npx -y @maildev/mcp

Then check that it loaded and tell me if I need to sign in or restart.
  2. 2

    Paste it into Claude Code. It shows the change and asks before running it.

Requires Node.js.

Built from the package data we hold. Not yet tested by us.

Tools

  • Finds test emails by text, sender, recipient, subject, date or read status

    Searches the inbox with any mix of free text, sender, recipient, subject, attachments, read status and a date range. Returns up to 20 matches by default, with a link to each in the MailDev web page.

    Try: “Find emails sent to test@example.com in the last hour that have an attachment.”

    Network · maildev_search_emails

  • Opens one email and shows its full content and attachment list

    Returns the whole email for an ID you give it, including the body and the list of attachments.

    Try: “Open that welcome email and show me the full text.”

    Network · maildev_get_email

  • Shows the most recent email, or the last few

    Returns the newest email in full, or the newest several if you ask for a count. Handy right after a test run.

    Try: “Show me the latest email MailDev received.”

    Network · maildev_get_latest_email

  • Downloads one attachment from an email

    Fetches a named attachment from an email and returns its size and contents as base64 text in the chat. Large files will fill the conversation.

    Try: “Get invoice.pdf from the receipt email.”

    Network · maildev_get_attachment

  • Deletes one email from the inbox

    Deletes the email with the ID you give it from the MailDev inbox. There is no undo.

    Try: “Delete the test email with the wrong subject line.”

    Delete · maildev_delete_email

Read from the source code

Permissions

high risk · 3 things to watch

High risk

It can read every email in the inbox and delete them one at a time. Keep the MailDev inbox to test mail only, and do not point the server at a MailDev instance that holds real messages.

What it can do

  • Read your data
  • Create and change things
  • Delete things
  • Read-only mode

Watch out for

  • It can delete emails, with no undo

    The delete tool removes an email for good. Ask the assistant to confirm before it deletes anything. github.com

  • Attachments are pasted into the chat

    The attachment tool returns the whole file as base64 text, which can be large. Only open attachments you need. github.com

  • Needs a running MailDev with its API

    The server only talks to the MailDev address you give it. Check the address before you start so it does not reach a shared inbox. github.com

Security advisories

No published security advisories as of Nov 1, 2026.

Technical details
Talks toMailDev server (default http://localhost:1080)
Sign-in and keysOptional API key, passed with --api-key or MAILDEV_API_KEY and sent as a Bearer header to the MailDev API.

Questions

Is the MailDev MCP server official?

Yes. It lives in the MailDev repository itself, under packages/mcp, and is published as @maildev/mcp.

Does it need an API key?

No. An API key is optional. If your MailDev API requires one, pass it with the --api-key flag or the MAILDEV_API_KEY variable.

Do I need MailDev running first?

Yes. The server reads from a running MailDev, at http://localhost:1080 by default. Change the address with the --url flag or the MAILDEV_API_URL variable.

Can it delete emails?

Yes. It has a tool that deletes one email by ID, and the source has no read-only switch. Use a MailDev inbox that holds test mail only.

Is it local or hosted?

Local. It runs on your computer over stdio and calls your MailDev server. The README also says the MailDev API server serves MCP at /mcp, which is a separate way to connect.

How do I add it to Claude or Cursor?

Use the install box above. The server's own help text shows a Claude Desktop config with the maildev-mcp command and the MAILDEV_API_URL variable.

Information

updated Nov 2, 2026

Publisher
Official
Package
@maildev/mcp
Registry
npm
Transport
stdio
Auth
None
Version
3.0.0
License
MIT
Last commit
Sep 24, 2026
Open issues
37

GitHubnpm

Sources

Docs, issue trackers and discussions this page is built from. Issues, quotes and findings above link to their own source.

Show all 3
  1. github.com · github.com
  2. github.com · github.com
  3. github.com · github.com

Facts from the official MCP registry, GitHub, npm, PyPI and the Docker catalog. Updated Nov 2, 2026.