Email Preflight MCP Server

by tasuyoapp-ctrl Your server? Claim it

answering

Email Preflight is answering right now. Last checked 4 min ago. It exposes 3 tools.

Email preflight x402: $0.001 USDC on Base. MCP returns unpaid 402 only; no signing or payment.

Uptime history 15 days of history · worst day 0%

15 days agonow

60.9%

Uptime 24h

56 of 92 checks

Tools

read from the server

309 ms

Response time

average over 24h

open, no key

Access

streamable-http

Email Preflight does not always answer

Over the last week it answered 8.7% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 4 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add email-preflight --transport http https://email-preflight-mcp.onrender.com/mcp

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "email-preflight": {
      "url": "https://email-preflight-mcp.onrender.com/mcp"
    }
  }
}

~/.codex/config.toml

[mcp_servers.email-preflight]
url = "https://email-preflight-mcp.onrender.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "email-preflight": {
      "url": "https://email-preflight-mcp.onrender.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "mcpServers": {
    "email-preflight": {
      "url": "https://email-preflight-mcp.onrender.com/mcp"
    }
  }
}

Available tools 3

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

email_check_mini

Check email syntax, MX and local domain classes with the existing API. $0.001 USDC on Base mainnet. MX does not prove mailbox existence. Unpaid calls return x402 v2 requirements for this request. A compatible client may repeat identical arguments with its own PaymentPayload in params._meta["x402/payment"]. The adapter does not sign or settle independently.

email_preflight

Use before sending or processing an email when you need current preflight facts about the address. For $0.001 USDC on Base mainnet, the existing Email Preflight API checks six facts: syntax validity, domain availability, MX availability, disposable-email detection, role-account detection, and free-provider detection. Example paid result shape: { email: "[email protected]", syntax: "valid", domain: "exists", mx: "found", disposable: "not_listed", role_based: "not_detected", free_provider: "not_detected" }. MX records do not prove that a mailbox exists. Unpaid requests return the original upstream HTTP 402 challenge. A compatible x402 client may retry with its own signed PaymentPayload in params._meta["x402/payment"]. This adapter never signs, owns a wallet, or settles independently.

url

url_preflight

Inspect public HTTP/HTTPS URL response metadata through the existing safe URL API. $0.001 USDC on Base mainnet. Unpaid calls return x402 v2 requirements. A compatible client may repeat the identical url argument with its own signed PaymentPayload in params._meta["x402/payment"]. This bridge does not fetch that URL directly, sign payments, or settle independently.

Endpoints

URL	Transport	State	Latency	Checked
https://email-preflight-mcp.onrender.com/mcp	streamable-http	answering	277 ms	4 min ago

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Email Preflight — questions

Answers built from our own checks of this server.

What can Email Preflight do?

It exposes 3 tools, read directly from the server on our last check. Among them: email_check_mini, email_preflight, url_preflight. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is Email Preflight working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 56 of 92 checks got a reply (60.9%), average response time 309 ms. The bar chart above shows every period we have measured.

How do I connect Email Preflight?

Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does Email Preflight need an API key?

No. Email Preflight completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 3 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is Email Preflight?

It answers our handshake in 309 ms on average, which is faster than 43% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.