Mailsnail runs on your own machine — the client starts it, so there is no endpoint to ping. 41 installs a week from npm. Last commit 7 Nov 2026.
Send USPS letters, postcards & certified mail from any agent. No signup; pay-per-piece via Stripe.
What the code does
We read the source, 6 d ago · rules 995398eba69f
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
const child = spawn(process.execPath, [SERVER], {
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
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 mailsnail -e 'MAIL_PROVIDER=<MAIL_PROVIDER>' -- npx -y mailsnail{
"mcpServers": {
"mailsnail": {
"command": "npx",
"args": [
"-y",
"mailsnail"
],
"env": {
"MAIL_PROVIDER": "<MAIL_PROVIDER>"
}
}
}
}[mcp_servers.mailsnail]
command = "npx"
args = ["-y", "mailsnail"]
env = { MAIL_PROVIDER = "<MAIL_PROVIDER>" }{
"mcpServers": {
"mailsnail": {
"command": "npx",
"args": [
"-y",
"mailsnail"
],
"env": {
"MAIL_PROVIDER": "<MAIL_PROVIDER>"
}
}
}
}{
"servers": {
"mailsnail": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"mailsnail"
],
"env": {
"MAIL_PROVIDER": "<MAIL_PROVIDER>"
}
}
}
}Put your own value in place of
<MAIL_PROVIDER> (Where to mail from: 'managed' (default, no signup, pay-per-piece via Stripe), 'click2mail' (BYO account), or 'lob' (BYO key)).
The author’s registry entry marks it as required.
Optional settings from the registry entry, left out of the block above:
MAIL_API_BASE_URL (Hosted Mailsnail backend. Required when MAIL_PROVIDER=managed), CLICK2MAIL_USERNAME (Click2Mail account username. Required when MAIL_PROVIDER=click2mail), CLICK2MAIL_PASSWORD (Click2Mail account password. Required when MAIL_PROVIDER=click2mail), LOB_API_KEY (Lob API key. Required when MAIL_PROVIDER=lob. test_* is free; live_* actually mails), MAIL_MCP_ALLOW_LIVE (Set to '1' to actually mail in BYOK modes. Default '0' is dry-run), MAIL_MCP_SPEND_CAP_USD (Per-session estimated spend cap. Server refuses sends past this).
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Mailsnail — questions
Answers built from our own checks of this server.