Email Verifier MCP

Email Verifier MCP

Verify email addresses without paying a per-lookup API fee. RFC 5321 syntax, MX records, a 182,000-domain disposable blacklist and role-account detection — all from free DNS. SMTP handshake is opt-in and off by default.

🌐 [English](#english) · [简体中文](#简体中文) · [繁體中文](#繁體中文)

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English

Current version: 1.0.0

What you get

Every product with a signup form needs to know whether an email is real. The usual answer is a paid API — SendGrid, Hunter, ZeroBounce — billed per lookup. This server does the checks that actually catch bad signups using free DNS queries and an open-source blocklist, so the marginal cost is zero.

It is built agent-native: point your agent at the hosted endpoint or run it locally — no dashboard, no account, no API key for the DNS checks.

Tools

Also exposed: resource blacklist://stats (blocklist size and source) and prompt verify_signup_email (an accept / flag / reject decision template).

Example

// request

{ "email": "someone@gmail.com" }

// response (structured) { "email": "someone@gmail.com", "valid": true, "score": 80, "reason": "DNS checks passed", "checks_passed": ["syntax", "mx", "blacklist", "role"], "mx_records": [{ "priority": 10, "exchange": "gmail-smtp-in.l.google.com" }], "disposable": false, "role_account": false }

Confidence score

The score is additive and fully explainable — no black box.

80/100 means every DNS check passed. The last 20 points require the optional SMTP handshake, which is off by default. valid is a separate boolean: it is true only when syntax passes, an MX record exists, and the domain is not disposable.

Connect

Option A — self-host via local clone (free, unlimited). Runs as a stdio subprocess inside your own agent:

{

"mcpServers": { "email-verifier-mcp": { "command": "npm", "args": ["start"], "cwd": "/absolute/path/to/Email-Verifier-MCP" } } }

The email-verifier-mcp package is not published to npm, so npx email-verifier-mcp will not resolve. Clone the repo (see the table above), run npm i && npm start, and point your client at it — or use the hosted endpoint (Option B).

Option B — hosted endpoint on Apify. Use it from anywhere, including agents that cannot spawn subprocesses:

{

"mcpServers": { "email-verifier-mcp": { "type": "streamable-http", "url": "https://neeenja--email-verifier-mcp.apify.actor/mcp", "headers": { "Authorization": "Bearer " } } } }

Works with Claude Desktop, Cursor, Windsurf, GitHub Copilot, and any other MCP client.

Compliance

Default verification is DNS-only — it never opens an outbound SMTP connection, so it cannot be mistaken for port-25 scanning.

The SMTP handshake is opt-in (smtp: true) and should only be enabled from infrastructure you control. Some mail providers treat unsolicited SMTP probes as abuse, and many return 250 to every RCPT TO specifically to defeat probing — so smtp_likely_valid is reported honestly as null when the answer is inconclusive rather than guessed.

Pricing

The hosted endpoint is pay-per-event: no subscription, no minimum. Running it locally (clone + npm start) costs nothing.

Development

npm install

npm run build # tsc -> dist/ npm test # unit tests npm run e2e # stdio end-to-end (initialize -> tools/list -> tools/call) npm run e2e:http # HTTP end-to-end (readiness probe + full protocol) npm run showcase # real-DNS demo -> verify-showcase.html

License

MIT. The disposable-domain list comes from disposable-email-domain (MIT, refreshed weekly).

Privacy

Read-only and stateless. Submitted email addresses are processed in memory only and are not stored; the opt-in SMTP handshake discloses the checking host's IP to the recipient's mail server. See PRIVACY.md.

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简体中文

你能得到什么

任何带注册环节的产品都要判断邮箱是不是真的。常见方案是付费 API —— SendGrid、Hunter、ZeroBounce 按次计费。本服务用免费 DNS 查询 + 开源黑名单完成真正有效的检查，边际成本为零。

它面向 Agent 设计：把 Agent 指向托管端点，或在本地自行运行 —— 不需要仪表盘、不需要账号、DNS 检查不需要 API key。

工具

另外还提供资源 blacklist://stats（黑名单规模与来源）与提示词 verify_signup_email（接受 / 标记 / 拒绝的决策模板）。

示例

// 请求

{ "email": "someone@gmail.com" }

// 响应（结构化） { "email": "someone@gmail.com", "valid": true, "score": 80, "reason": "DNS checks passed", "checks_passed": ["syntax", "mx", "blacklist", "role"], "mx_records": [{ "priority": 10, "exchange": "gmail-smtp-in.l.google.com" }], "disposable": false, "role_account": false }

置信度评分

评分是累加式的，完全可解释，不是黑盒。

80/100 代表所有 DNS 检查全部通过。 最后 20 分需要可选的 SMTP 握手，而它默认是关闭的。valid 是独立的布尔值：只有语法通过、MX 存在、且非一次性域名时才为 true。

连接方式

方式 A —— 本地克隆自托管（免费、无限次）。在你的 Agent 进程内以 stdio 子进程运行：

{

"mcpServers": { "email-verifier-mcp": { "command": "npm", "args": ["start"], "cwd": "/absolute/path/to/Email-Verifier-MCP" } } }

email-verifier-mcp 暂未发布到 npm，因此 npx email-verifier-mcp 无法解析。请克隆仓库（见上方表格），运行 npm i && npm start，再将你的客户端指向它 —— 或使用托管端点（方式 B）。

方式 B —— Apify 托管端点。任何地方都能调用，包括无法启动子进程的 Agent：

{

"mcpServers": { "email-verifier-mcp": { "type": "streamable-http", "url": "https://neeenja--email-verifier-mcp.apify.actor/mcp", "headers": { "Authorization": "Bearer " } } } }

兼容 Claude Desktop、Cursor、Windsurf、GitHub Copilot 及任何其他 MCP 客户端。

合规说明

默认校验仅使用 DNS —— 不建立任何出站 SMTP 连接，因此不会被误判为 25 端口扫描。

SMTP 握手是可选开启的（smtp: true），只应在你能掌控的基础设施上启用。部分邮件服务商会把未经请求的 SMTP 探测视为滥用，且很多服务会对所有 RCPT TO 一律返回 250 来反探测 —— 因此当结论不明确时，smtp_likely_valid 会诚实地返回 null，而不是猜一个结果。

定价

托管端点按次计费：无订阅、无最低消费。本地克隆运行（npm start）不产生任何费用。

本地开发

npm install

npm run build # tsc -> dist/ npm test # 单元测试 npm run e2e # stdio 端到端（initialize -> tools/list -> tools/call） npm run e2e:http # HTTP 端到端（就绪探针 + 完整协议） npm run showcase # 真实 DNS 演示 -> verify-showcase.html

许可

MIT。一次性域名列表来自 disposable-email-domain（MIT，每周更新）。

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繁體中文

你能得到什麼

任何帶註冊環節的產品都要判斷信箱是不是真的。常見做法是付費 API —— SendGrid、Hunter、ZeroBounce 按次計費。本服務用免費 DNS 查詢 + 開源黑名單完成真正有效的檢查，邊際成本為零。

它為 Agent 而生：把 Agent 指向託管端點，或在本地自行執行 —— 不需要儀表板、不需要帳號、DNS 檢查不需要 API key。

工具

另外提供資源 blacklist://stats（黑名單規模與來源）與提示詞 verify_signup_email（接受 / 標記 / 拒絕的決策範本）。

範例

// 請求

{ "email": "someone@gmail.com" }

// 回應（結構化） { "email": "someone@gmail.com", "valid": true, "score": 80, "reason": "DNS checks passed", "checks_passed": ["syntax", "mx", "blacklist", "role"], "mx_records": [{ "priority": 10, "exchange": "gmail-smtp-in.l.google.com" }], "disposable": false, "role_account": false }

信心分數

分數採累加式，完全可解釋，不是黑盒子。

80/100 代表所有 DNS 檢查全數通過。 最後 20 分需要可選的 SMTP 握手，而它預設關閉。valid 是獨立的布林值：只有語法通過、MX 存在、且非一次性網域時才為 true。

連線方式

方式 A —— 本機克隆自託管（免費、無限量）。在你的 Agent 行程內以 stdio 子行程執行：

{

"mcpServers": { "email-verifier-mcp": { "command": "npm", "args": ["start"], "cwd": "/absolute/path/to/Email-Verifier-MCP" } } }

email-verifier-mcp 尚未發佈到 npm，因此 npx email-verifier-mcp 無法解析。請克隆倉庫（見上方表格），執行 npm i && npm start，再將你的用戶端指向它 —— 或使用託管端點（方式 B）。

方式 B —— Apify 託管端點。任何地方都能呼叫，包含無法啟動子行程的 Agent：

{

"mcpServers": { "email-verifier-mcp": { "type": "streamable-http", "url": "https://neeenja--email-verifier-mcp.apify.actor/mcp", "headers": { "Authorization": "Bearer " } } } }

相容 Claude Desktop、Cursor、Windsurf、GitHub Copilot 以及任何其他 MCP 用戶端。

合規說明

預設驗證僅使用 DNS —— 不建立任