Millionverifier MCP Server

@pipeworx/millionverifier

Verify a single email address via MillionVerifier (millionverifier.com). Part of enrich-waterfall's enrich_verify_email ordered verifiers (fleet #2860).

Part of Pipeworx — an MCP gateway connecting AI agents to 1743+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

Tools

• millionverifier_verify(email, timeout?, _apiKey) — result (ok/catch_all/disposable/invalid/unknown), explicit catch_all boolean, quality, free/role flags.

Auth

BYO only. Pass your MillionVerifier API key as _apiKey (sent as the api QUERY PARAM on a GET request). Find your key at https://app.millionverifier.com/api. No platform key (D4).

Data sources

• https://api.millionverifier.com/api/v3/ — single email verify.

Verification notes (fleet #2860, 2026-10-08, no vendor key held)

• TRAP, confirmed live by edge probe: MillionVerifier returns HTTP 200 on an auth failure. Invalid key:

  GET https://api.millionverifier.com/api/v3/?api=invalidkey123&email=test@example.com
  -> HTTP 200
  {"email":"test@example.com","result":"error","resultcode":4,"subresult":"",
   "free":false,"role":false,"didyoumean":"","credits":0,"executiontime":0,
   "error":"Apikey not found","livemode":true}
  

  A res.ok check alone would not catch this — the pack checks result === 'error' (or a present error string) and throws, rather than handing back result: "error" as though it were a verdict about the email address. This is exactly the silent-200 shape the house rules flag: a 200 with a payload that LOOKS like a normal result but means "the call itself failed."
• Response field names and catch_all representation confirmed from vendor docs (https://developer.millionverifier.com/, read 2026-10-08): result includes catch_all as a first-class value (not a separate flag on top of "ok") — this pack derives catch_all: result === 'catch_all' so the caller still gets a stable boolean field.
• Not verified (no key held): the full enumeration of result values beyond what the docs and the error probe showed (ok, catch_all, unverified, invalid, unknown, disposable, error were all that surfaced); exact resultcode -> result mapping.

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

{
  "mcpServers": {
    "millionverifier": {
      "url": "https://gateway.pipeworx.io/millionverifier/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/millionverifier/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1743+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

This pack takes your own API key (_apiKey) — we don't front one for it, so there's no curl here that would run without it. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/millionverifier_verify. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no gateway round-trip:

{
  "mcpServers": {
    "millionverifier": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-millionverifier"]
    }
  }
}

Or run it directly to confirm it starts:

npx -y @pipeworx/mcp-millionverifier

It speaks MCP over stdin/stdout and answers initialize/tools/list/tools/call for only this pack's tools — none of the shared meta-tools the gateway connection above adds. Same source, same tools, no ask_pipeworx routing.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

ask_pipeworx({ question: "your question about Millionverifier data" })

The gateway picks the right tool and fills the arguments automatically.

More

• Docs and guides
• pipeworx.io

License

MIT