MailboxValidator runs on your own machine — the client starts it, so there is no endpoint to ping. 38 installs a week from npm. Last commit 26 Oct 2026.
Email validation MCP server using the MailboxValidator API. It can validate email addresses.
Nothing serious here today
Today is the operative word: we check MailboxValidator every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
Connect this server
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add mcp-mailboxvalidator -e 'MAILBOXVALIDATOR_API_KEY=<MAILBOXVALIDATOR_API_KEY>' -- npx -y mcp-mailboxvalidator{
"mcpServers": {
"mcp-mailboxvalidator": {
"command": "npx",
"args": [
"-y",
"mcp-mailboxvalidator"
],
"env": {
"MAILBOXVALIDATOR_API_KEY": "<MAILBOXVALIDATOR_API_KEY>"
}
}
}
}[mcp_servers.mcp-mailboxvalidator]
command = "npx"
args = ["-y", "mcp-mailboxvalidator"]
env = { MAILBOXVALIDATOR_API_KEY = "<MAILBOXVALIDATOR_API_KEY>" }{
"mcpServers": {
"mcp-mailboxvalidator": {
"command": "npx",
"args": [
"-y",
"mcp-mailboxvalidator"
],
"env": {
"MAILBOXVALIDATOR_API_KEY": "<MAILBOXVALIDATOR_API_KEY>"
}
}
}
}{
"servers": {
"mcp-mailboxvalidator": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"mcp-mailboxvalidator"
],
"env": {
"MAILBOXVALIDATOR_API_KEY": "<MAILBOXVALIDATOR_API_KEY>"
}
}
}
}Put your own value in place of
<MAILBOXVALIDATOR_API_KEY> (Your MailboxValidator API key).
The author’s registry entry marks it as required.
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MailboxValidator — questions
Answers built from our own checks of this server.