Mailsink
@heocoi
About Mailsink
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.
Config
Add this server to your MCP-compatible client using the configuration below.
{
"mcpServers": {
"mailsink": {
"command": "npx",
"args": [
"-y",
"@mailsink/mcp"
],
"env": {
"MAILSINK_API_KEY": "msk_..."
}
}
}
}Tools
8Create a temporary email inbox. Returns the email address to use for signups/verification.
Wait for an email to arrive in an inbox. Polls until a message appears or timeout.
Get the most recent OTP/verification code from an inbox. Polls if no code found yet.
Get the most recent verification/magic link from an inbox. Polls if no link found yet.
List all messages in an inbox.
Get the full content of a specific message.
Delete an inbox and all its messages.
List all active (non-expired) inboxes.
Overview
What is Mailsink?
Mailsink is a Model Context Protocol (MCP) server that provides programmatic temporary email inboxes for AI agents and test automation. It gives agents eight typed tools for provisioning disposable addresses, waiting on signup emails, extracting OTP codes and magic links, and cleaning up after themselves. Works with Claude Code, Claude Desktop, Cursor, Windsurf, and any MCP-aware client.
How to use Mailsink?
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.
Key features of Mailsink
- 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
Use cases of Mailsink
- AI agent signs up for a service and captures a verification code or magic link
- Test automation creates temporary inboxes, validates signup emails, and cleans up
- Extract one-time passwords (OTPs) from signup or login emails automatically
- Demo or integration testing requiring disposable email addresses
FAQ from Mailsink
What is the free tier and pricing?
Free tier includes 50 inboxes per month and MCP access. Pro ($15/mo) and Team ($49/mo) raise inbox caps, email size limits, TTL, and request rates.
How do I get an API key?
Sign in at mailsink.dev/app with GitHub, copy the one-time reveal key, and export it as MAILSINK_API_KEY environment variable.
What MCP clients are supported?
Claude Code, Claude Desktop, Cursor, and Windsurf, plus any other MCP-aware client.
What environment variables are required?
MAILSINK_API_KEY (required). Optionally MAILSINK_API_URL to override the default API endpoint.
How are emails fetched and how long can the server wait?
The wait_for_email tool blocks up to a configurable timeout (max 120 seconds) for any email to arrive. No persistent storage or webhook setup needed.
Frequently asked questions
What is the free tier and pricing?
Free tier includes 50 inboxes per month and MCP access. Pro ($15/mo) and Team ($49/mo) raise inbox caps, email size limits, TTL, and request rates.
How do I get an API key?
Sign in at mailsink.dev/app with GitHub, copy the one-time reveal key, and export it as `MAILSINK_API_KEY` environment variable.
What MCP clients are supported?
Claude Code, Claude Desktop, Cursor, and Windsurf, plus any other MCP-aware client.
What environment variables are required?
`MAILSINK_API_KEY` (required). Optionally `MAILSINK_API_URL` to override the default API endpoint.
How are emails fetched and how long can the server wait?
The `wait_for_email` tool blocks up to a configurable timeout (max 120 seconds) for any email to arrive. No persistent storage or webhook setup needed.
Basic information
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