MCP server

Postbox Tools

com.postboxservices/postbox-tools

Checked 26 Oct 2026, 08:29 UTC · Connected to it and listed its tools

Free email checks: 24 blacklists, spoofing/BEC grade, redirect tracing, email spam test, WHOIS.

Website

At a glance

Type

MCP server

Publisher

postboxservices.com (verified by the MCP Registry)

Status

Working at last check

Tools

8

Token cost

About 1,114 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

26 Oct 2026, 08:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http postbox-tools https://mcp.postboxservices.com/mcp

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.postbox-tools]
url = "https://mcp.postboxservices.com/mcp"

Gemini CLI

{"mcpServers":{"postbox-tools":{"httpUrl":"https://mcp.postboxservices.com/mcp"}}}

Cursor

{"mcpServers":{"postbox-tools":{"url":"https://mcp.postboxservices.com/mcp"}}}

VS Code

{"servers":{"postbox-tools":{"type":"http","url":"https://mcp.postboxservices.com/mcp"}}}

Antigravity

agy mcp add postbox-tools https://mcp.postboxservices.com/mcp

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"postbox-tools","server_url":"https://mcp.postboxservices.com/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"postbox-tools","server_url":"https://mcp.postboxservices.com/mcp"}

Tools

• analyze_eml ~170 tokens
  Run a deliverability/content analysis on a raw RFC 822 email (.eml source: full headers + body). IMPORTANT LIMITS: with no live SMTP session, SPF, blacklist and reverse-DNS cannot be verified from a file - for the authoritative score use create_mailtest instead.
• check_blacklist ~170 tokens
  Check a domain against domain blacklists (Spamhaus DBL, SURBL, URIBL and others), or an IP address against 24 IP blacklists including Spamhaus ZEN, Barracuda and SpamCop. Checks the exact target given: domains are not resolved to IPs. Returns per-list listing status.
• check_spoofability ~136 tokens
  Grade how exposed a domain is to email spoofing and business email compromise, from its public DNS (SPF, DMARC policy strength, alignment, live lookalike domains). Returns an A-F grade with findings.
• create_mailtest Sends messages · ~138 tokens
  Create a disposable test address for a full email deliverability audit (score /10: SPF, DKIM, DMARC + alignment, blacklists, reverse DNS, SpamAssassin content, Gmail/Yahoo bulk-sender compliance). The USER must then send an email from the system they want to test to the returned address, after which
• get_domain_age ~100 tokens
  Get a domain's registration date and age (young domains have weak sending reputation).
• get_mailtest_result ~117 tokens
  Fetch the score and breakdown of a mail test created with create_mailtest, once the user has sent their email to the disposable address.
• trace_redirect ~179 tokens
  Follow a URL server-side through every HTTP redirect hop to its real final destination - per-hop status, IP, TLS and timing, plus phishing/deliverability flags (cross-domain jumps, https downgrades, meta/JS redirects). Fetching is SSRF-hardened (private ranges blocked, HTTPS-only, per-hop validation
• whois_lookup ~104 tokens
  WHOIS summary for a domain: registrar, created/updated/expires dates, nameservers, DNSSEC, status flags.

Browse

• Domains and DNS
• Email

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Badge for your README

[![AptLynx](https://aptlynx.net/badge/com.postboxservices/postbox-tools.svg)](https://aptlynx.net/servers/com.postboxservices/postbox-tools)

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