drwho.me

Free tools for domains, mail and the web.

Most of them run in your browser, so what you look up stays with you. The same tools are open to AI agents through a free MCP server.

32tools, no account

Email

  1. 01SPF checkerFind and read a domain's SPF record.In your browser
  2. 02DMARC checkerRead the DMARC policy at _dmarc.In your browser
  3. 03DKIM lookupProbe 21 common DKIM selectors.In your browser
  4. 04TLS-RPT checkerLook up the SMTP TLS reporting policy.In your browser
  5. 05MTA-STS checkerFetch and validate the MTA-STS policy.On our server
  6. 06Blacklist checkCheck mail and web IPs against six blocklists.In your browser
  7. 07SPF generatorBuild an SPF record and count its lookups.In your browser
  8. 08DMARC generatorBuild a DMARC record, with warnings.In your browser

DNS

  1. 09DNS lookupResolve one record type.In your browser
  2. 10DNS recordsA, AAAA, NS, SOA, CAA and TXT in one go.In your browser
  3. 11MX lookupMail servers, sorted by priority.In your browser
  4. 12DNSSEC checkerDS, DNSKEY and the validation flag.In your browser

Site checks

  1. 13Security headersHSTS, CSP and the rest, as served.On our server
  2. 14TLS certificateIssuer, expiry, names and fingerprint.On our server
  3. 15Redirect chainEvery hop from https://domain/.On our server
  4. 16CORS checkerRun a preflight and read the answer.On our server
  5. 17Web surfacerobots.txt, sitemap and page metadata.On our server
  6. 18AI-crawler policyWhat robots.txt tells GPTBot, ClaudeBot and others.On our server
  7. 19llms.txt checkerIs there an llms.txt for AI agents?On our server
  8. 20security.txt checkerIs there a way to report a vulnerability?On our server
  9. 21MCP endpoint checkerDoes an MCP endpoint answer, and does it need auth?On our server

Discovery

  1. 22WHOIS lookupRegistrar, created and expiry dates.On our server
  2. 23Certificate log lookupSubdomains seen in certificate transparency logs.On our server

Your connection

  1. 24What is my IPYour public address, location and network.On our server
  2. 25IP lookupLocation, network and owner of any address.On our server
  3. 26Request headersThe headers your browser sends.On our server
  4. 27User agent parserBrowser, system and device from a UA string.In your browser

Developer

  1. 28Base64Encode and decode, including base64url.In your browser
  2. 29JWT decoderRead a token's header and claims. Nothing leaves the page.In your browser
  3. 30JSON formatterFormat, minify and validate.In your browser
  4. 31URL encoderPercent-encode and decode.In your browser
  5. 32UUID generatorVersion 4 and version 7.In your browser