mcpField
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Mailsink

Mailsink

Local
github.com/heocoiCommunication0Updated 10w ago
Repository

About Mailsink

Mailsink is an MCP server for creating and managing temporary email inboxes, designed for QA workflows and AI agents. Its tools cover incoming-message waits, OTP and magic-link extraction, and inbox cleanup.

Key features

  1. 01Create disposable inboxes
  2. 02List active inboxes
  3. 03Wait for incoming email
  4. 04Extract OTP codes and magic links
  5. 05Read message summaries and contents
  6. 06Delete inboxes

Use cases

  1. 01Test email-based account registration
  2. 02Retrieve OTPs during automated QA
  3. 03Follow magic links in agent workflows
  4. 04Remove temporary inboxes after tests

MCP support

The server exposes eight typed tools to MCP clients for provisioning inboxes, retrieving email content and verification data, and deleting inboxes. It can be run with `npx @mailsink/mcp` and requires `MAILSINK_API_KEY`.

#email#testing#automation#qa#mailsink#temp-email#otp#verification

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "mailsink": {
      "command": "npx",
      "args": [
        "-y",
        "@mailsink/mcp"
      ],
      "env": {
        "MAILSINK_API_KEY": "<MAILSINK_API_KEY>",
        "MAILSINK_API_URL": "<MAILSINK_API_URL>"
      }
    }
  }
}
Run commandnpx -y @mailsink/mcp
Environment variables to set
MAILSINK_API_KEYSecretYour MailSink API key. Get it at https://mailsink.dev/auth/github
MAILSINK_API_URLOptional API base URL override (defaults to https://api.mailsink.dev)

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
npm@mailsink/mcp0.1.5

Tools

8

Saved tool list · updated 3w ago

ParameterTypeRequiredDescription
domainstringNoCustom domain (BYOD). Omit to use shared domain.
local_partstringNoOptional prefix for the email address (e.g. "test-signup")
ttlnumberNoTime-to-live in seconds (default: max for your plan)

Details

From the project README

@mailsink/mcp

Model Context Protocol server for MailSink — programmatic temporary email inboxes for AI agents and test automation.

Gives your agent eight typed tools for provisioning disposable addresses, waiting on signup emails, extracting OTP codes and magic links, and cleaning up after itself. Works in Claude Code, Claude Desktop, Cursor, Windsurf, and any other MCP-aware client.

Install

npm install -g @mailsink/mcp

Or run via npx without installing:

npx @mailsink/mcp

Get an API key

  1. Sign in at https://mailsink.dev/app with GitHub.

  2. Copy the key from the one-time reveal. Store it in your password manager or .env.

  3. Export it so the MCP server can read it:

    export MAILSINK_API_KEY="msk_..."

Free tier is 50 inboxes/month and includes MCP. Pro ($15/mo) and Team ($49/mo) lift the inbox cap, raise email size limits, extend TTL, and bump request rates. See pricing.

Configure your client

Claude Code
claude mcp add mailsink -- npx -y @mailsink/mcp
Claude Desktop / Cursor / Windsurf

Add to the mcpServers section of the client's config file:

{
  "mcpServers": {
    "mailsink": {
      "command": "npx",
      "args": ["-y", "@mailsink/mcp"],
      "env": {
        "MAILSINK_API_KEY": "msk_..."
      }
    }
  }
}

Restart the client. You should see the mailsink server listed with its eight tools.

Tools

ToolPurpose
create_inboxProvision a throwaway address. Returns email, id, expires_at.
list_inboxesList active inboxes on the account.
wait_for_emailBlock up to timeout seconds (max 120) for any email to arrive.
get_verification_codeExtract the most recent OTP from the inbox (polls until found or timeout).
get_verification_linkExtract the most recent magic link.
list_messagesSummaries of all messages in an inbox.
get_messageFull content of a specific message by ID.
delete_inboxBurn an inbox immediately.

Example agent flow

> Sign me up for Figma, capture the verification code, confirm, and
> tell me the plan once you're in.

[agent invokes]
  create_inbox()                                → [email protected]
  [agent fills the Figma signup form with that address]
  wait_for_email(inbox_id)                      → blocks 30s…
                                                → returns email + OTP
  [agent types the OTP into the Figma form]
  delete_inbox(inbox_id)                        → cleanup

No webhook plumbing. No IMAP credentials. No parsing MIME.

Environment variables

  • MAILSINK_API_KEY (required) — your account's API key.
  • MAILSINK_API_URL (optional, default https://api.mailsink.dev) — override for self-hosted or dev API.

Source

https://github.com/heocoi/mailsink/tree/main/mcp

License

MIT — see LICENSE.

Comments

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New to MCP?

From what the protocol is to installing your first server, these answers cover most first questions.

An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.