Skip to content
MtrXTools

About MtrXTools

MtrXTools is a free suite of network diagnostic tools for the people who keep websites, mail and networks running: system administrators, DevOps and network engineers, developers, and anyone who has just been told “it's a DNS problem”. It brings the checks those people usually run from several different sites and command-line tools into one place, with results explained in plain language.

What it covers

There are 56 live tools in 8 areas:

  • DNS: Records, delegation and how the world resolves you.
  • Website: Certificates, headers and what a browser sees.
  • Email: Authentication, deliverability and header forensics.
  • Lookup: Who owns a domain, IP or network.
  • Connectivity: Reachability, latency and the path between.
  • IP & subnets: Subnet maths, IPv6 and MAC addresses, worked out in your browser.
  • Certificates & keys: Decode, convert and generate certificates, keys and DANE records in your browser.
  • Developer tools: Encoders, decoders and formatters that run in your browser.

Alongside the tools, the error explainer library describes 281 common error messages from browsers, command-line tools, programming languages, web servers and mail servers: what each one means, the usual causes, how to fix it, and which check confirms the cause.

How the checks work

  • Network checks (DNS, TLS, HTTP, mail authentication, ports, routing) run from our servers on the public internet, so you see what your visitors and other mail servers see. DNS queries use our own resolver client rather than a cache you can't control.
  • Every check is passive and read-only: the same standard requests browsers and mail servers make every day. MtrXTools never sends attack traffic, exploits, login attempts or scans, and refuses to contact private or internal addresses.
  • Decoders, converters and calculators (certificates, keys, JWTs, SAML, Base64, subnets and others) run entirely in your browser. What you paste into them is never uploaded.
  • Results aren't stored. Recent runs are kept only in your own browser, and every result page has a shareable link that re-runs the check.

For scripts and AI assistants

The same checks are available as a free JSON API and as an MCP server for AI assistants, with no key or sign-up. See the developer documentation.

Contact

Suggestions, bug reports and requests for new tools are welcome. See the contact page.