X509 MCP Server

by mrfentmen Your server? Claim it

local only

X509 MCP runs on your own machine — the client starts it, so there is no endpoint to ping. 597 installs a week from npm. Last commit 28 Oct 2026.

Decode PEM certificates, check expiry and inspect a live TLS certificate, all offline

Installs per day peak 513 · avg 19

a month agotoday

597

Installs / week

npm · @mrfentmen/x509-mcp

Stars

0 open issues

28 Oct 2026

Last commit

from GitHub

—

License

TypeScript

Nothing serious here today

Today is the operative word: we check X509 MCP every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add x509-mcp -- npx -y @mrfentmen/x509-mcp

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

{
  "mcpServers": {
    "x509-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@mrfentmen/x509-mcp"
      ]
    }
  }
}

~/.codex/config.toml

[mcp_servers.x509-mcp]
command = "npx"
args = ["-y", "@mrfentmen/x509-mcp"]

.cursor/mcp.json

{
  "mcpServers": {
    "x509-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@mrfentmen/x509-mcp"
      ]
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "x509-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@mrfentmen/x509-mcp"
      ]
    }
  }
}

Alternatives to X509 MCP

same job, measured the same way

Ssl Cert MCP

by mrfentmen

Inspect TLS certificates of a host: issuer, expiry, and SAN. No key required.

79 installs/wk local only

JWT Forge MCP

by ryudi84

Decode and inspect JWT tokens — header, payload, expiry check

91 installs/wk local only

Domain Osint MCP

by robertoyanguas-ops

Inspects live IPv4/IPv6 DNS resolution, TLS certificate issuer/expiry, and HTTP security grade.

2 tools answering

SSL Certificate Check

by powmcp

Inspect one endpoint's served certificate, expiry, hostname coverage, and accepted TLS versions.

1 tools answering

Soma

by medianemi-beep

Execution-verified code generation and verification with signed, offline-checkable certificates.

42 installs/wk local only

AgentDiet Domain OSINT, TLS Certificate & Security Headers Recon

by agentdiet

Inspects live IPv4/IPv6 DNS resolution, TLS certificate issuer/expiry, and HTTP security grade.

2 tools answering

Uptime MCP

by mrfentmen

Check website availability, latency, and TLS certificate expiry locally. No key required.

70 installs/wk local only

Boring Utils Expiry Watch

by hal-boring-utils

Check a site's TLS certificate and its domain registration expiry. Read-only, no sign-in.

2 tools answering

X509 MCP — questions

Answers built from our own checks of this server.

Why is there no uptime for X509 MCP?

X509 MCP runs on your own machine over stdio — there is no network address to reach, so uptime cannot be measured for it by anyone. What can be measured is adoption: the npm package @mrfentmen/x509-mcp was installed 597 times last week.

How do I connect X509 MCP?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It runs locally, so the command pulls @mrfentmen/x509-mcp straight from npm; nothing to host, nothing to sign up for.

How many people use X509 MCP?

The npm package @mrfentmen/x509-mcp was installed 597 times in the last week. We show installs rather than GitHub stars on purpose: a star is a bookmark, an install is someone actually running it.

Is X509 MCP open source?

We cannot say either way: written in TypeScript and 0 stars on GitHub, but we could not determine the licence, and without one the code is not open source by default.