Emaillistchecker.io Email Verification

io.emaillistcheckerv1.0.1Updated Oct 9, 2026

Verify emails (valid/invalid/risky/unknown): MX, SMTP, catch-all, disposable. Free agent key.

VerifiedStreamable HTTPWeb executableBusiness & CommerceCommunication & Collaboration

Overview

AI-generated overview

Lets an assistant verify whether email addresses can receive mail, returning valid, invalid, risky or unknown verdicts.

What it does
A hosted remote MCP server for email verification. Tools include verify_email for a single address, verify_batch for up to 25 addresses per call, get_batch_status, list_lists and get_list for saved verification lists, explain_result for a plain-English explanation and send recommendation, and estimate_cost and get_credit_balance for checking credits. Verdicts are valid, invalid, risky or unknown, based on MX, SMTP, catch-all and disposable checks.
When to use it
Use it before sending mail to a list or signup address, to filter out undeliverable, catch-all, role or disposable addresses. Useful for agents that collect or clean email addresses and want a send recommendation before acting.
Requirements
Remote Streamable HTTP endpoint; nothing to install. An API key is sent as the Authorization header in the form Bearer . A free key can be obtained without an account via the get_api_key tool or the registration endpoint; it allows 25 verifications per day and expires after 30 days. Network access to the hosted endpoint is required.
Before you install
The Authorization header carries a secret API key; the key is shown once, so store it safely. Verification sends the email address to a third-party service. Free keys are limited to 25 verifications per day, 10 requests per minute, one request in flight, and a shared daily capacity that returns HTTP 429 when exhausted. Batch verification consumes one credit per address.

Installation

In SourceWeft

  1. Open Emaillistchecker.io Email Verification in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "email-verification": {
      "type": "http",
      "url": "https://platform.emaillistchecker.io/mcp"
    }
  }
}

README

Emaillistchecker.io MCP server — email verification for AI agents

Remote Model Context Protocol server that tells an AI agent whether an email address can receive mail before anything is sent to it.

The server is hosted; there is nothing to install. This repository documents how to connect.

Get a key (no account needed)

Connect without a key and call the get_api_key tool, or:

bash
curl -X POST https://platform.emaillistchecker.io/agent-gateway/register \  -H 'Content-Type: application/json' \  -d '{"name":"my-agent","purpose":"verify signup emails"}'

The key is shown once. Each key gets 25 free verifications per day (unused credits do not roll over) and expires after 30 days; register again when it does. Send it as Authorization: Bearer <api_key>.

Connect

Claude Code

bash
claude mcp add --transport http emaillistchecker https://platform.emaillistchecker.io/mcp --header "Authorization: Bearer YOUR_KEY"

Claude Desktop / Cursor / VS Code (mcp.json-style config)

json
{  "mcpServers": {    "emaillistchecker": {      "type": "http",      "url": "https://platform.emaillistchecker.io/mcp",      "headers": { "Authorization": "Bearer YOUR_KEY" }    }  }}

Tools

ToolWhat it does
get_api_keyGet a free key (works without a key)
verify_emailVerify one address → valid, invalid, risky or unknown (1 credit)
verify_batchVerify up to 25 addresses per call, with per-address verdicts
get_batch_status, list_lists, get_listFollow saved verification lists
explain_resultExplain a verdict in plain English, with a send recommendation
estimate_cost, get_credit_balanceCheck credits before running

Verdicts

  • valid: the mailbox exists and accepts mail
  • invalid: the address or domain cannot receive mail
  • risky: accept-all (catch-all) domain, role or disposable address, or a Microsoft 365 address the mail server couldn't confirm
  • unknown: the receiving server gave no definitive answer

Limits

10 requests per minute per key, one request in flight per key, and a shared daily capacity for free agent keys (HTTP 429 until 00:00 UTC when it is used up). Inbox placement, blacklist monitoring and email finder need a full account at https://www.emaillistchecker.io.

REST API

The same key works on the REST API: POST https://platform.emaillistchecker.io/api/v1/verify, POST https://platform.emaillistchecker.io/api/v1/verify/batch, GET https://platform.emaillistchecker.io/api/v1/credits. See the OpenAPI description.

Source: README.md at commit af88ad3

Tools

0
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Version history

1
  1. v1.0.1LatestOct 9, 2026