Mailsink

by heocoi

313 downloads

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GitHub

About

Programmatic temp email inboxes for QA tests and AI agents. 8 MCP tools, free tier 50 inboxes/month, MCP server published as @mailsink/mcp on npm.

Details

Author: heocoi
Downloads: 313
Categories: Other, Developer Tools, Automation

- Eight typed MCP tools for email workflow automation
- Provision disposable inboxes with create_inbox
- Wait for incoming emails with configurable timeout (up to 120s)
- Extract OTP codes and magic links from received emails
- List, read, and delete inboxes programmatically
- No webhooks, IMAP, or MIME parsing required

Setting up with Highlight

This MCP is not yet compatible with Highlight’s one-click setup. However, you can still use it with Highlight by following these steps:

Download and install Highlight from highlightai.com/download
Navigate to the plugins tab and select "Add Custom Plugin"
Configure the plugin with the settings below

Plugin Name Mailsink

Command (node, npx, python, etc.)

Please refer to the README for specific instructions on how to obtain API keys or other required environment variables.
Enable "Start Automatically" if you want the plugin to start when Highlight launches

Setting up with Cursor

Open Cursor's settings
Navigate to the MCP section
Click "Add new Global MCP server"
Copy and paste the configuration below based on your operating system

JSON

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

JSON

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

JSON

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

Setting up with Claude Desktop

Open Claude Desktop's settings
Go to the Integrations tab
Click "Add MCP Server"
Use the configuration below based on your operating system

Note: Make sure Claude Desktop is running before attempting to connect.

JSON

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

JSON

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

JSON

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

Setting up with Windsurf

Open Windsurf's preferences
Go to the Integrations section
Click "Add MCP Integration"
Use the configuration below based on your operating system

JSON

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

JSON

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

JSON

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

Setting up with Cline

Open Cline's settings
Navigate to the Integrations section
Click "Add MCP Server"
Copy and paste the configuration below based on your operating system

Note: Make sure to restart Cline after adding the configuration.

JSON

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

JSON

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

JSON

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

Setting up with Goose

Open Goose's preferences
Go to the Integrations tab
Select "MCP Servers"
Click "Add New Server"
Use the configuration below based on your operating system

JSON

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

JSON

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

JSON

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

From the repository

Install globally via npm install -g @mailsink/mcp or run with npx -y @mailsink/mcp. Requires a free API key from mailsink.dev (exported as MAILSINK_API_KEY). Configure the client's mcpServers section with command npx and args ["-y", "@mailsink/mcp"] plus MAILSINK_API_KEY in env. Restart the client to see eight tools like create_inbox, wait_for_email, get_verification_code, etc.

`create_inbox`

Create a temporary email inbox. Returns the email address to use for signups/verification.

`wait_for_email`

Wait for an email to arrive in an inbox. Polls until a message appears or timeout.

`get_verification_code`

Get the most recent OTP/verification code from an inbox. Polls if no code found yet.

`get_verification_link`

Get the most recent verification/magic link from an inbox. Polls if no link found yet.

`list_messages`

List all messages in an inbox.

`get_message`

Get the full content of a specific message.

`delete_inbox`

Delete an inbox and all its messages.

`list_inboxes`

List all active (non-expired) inboxes.

Claude Desktop / Cursor

Paste into your MCP client config file to install this server.

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

McpServers

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

@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

| Tool | Purpose |
|---|---|
| create_inbox | Provision a throwaway address. Returns email, id, expires_at. |
| list_inboxes | List active inboxes on the account. |
| wait_for_email | Block up to timeout seconds (max 120) for any email to arrive. |
| get_verification_code | Extract the most recent OTP from the inbox (polls until found or timeout). |
| get_verification_link | Extract the most recent magic link. |
| list_messages | Summaries of all messages in an inbox. |
| get_message | Full content of a specific message by ID. |
| delete_inbox | Burn 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()                                → agent@codenotify.net

  [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.

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About

Details

Jump to

Setting up with Highlight

From the repository

create_inbox

wait_for_email

get_verification_code

get_verification_link

list_messages

get_message

delete_inbox

list_inboxes

Claude Desktop / Cursor

McpServers

@mailsink/mcp

Install

Get an API key

Configure your client

Claude Code

Claude Desktop / Cursor / Windsurf

Tools

Example agent flow

Environment variables

Source

License

Install

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`create_inbox`

`wait_for_email`

`get_verification_code`

`get_verification_link`

`list_messages`

`get_message`

`delete_inbox`

`list_inboxes`