Runs on our serverDNS and email health checkMX, SPF, DKIM, DMARC and blocklists for a domain, with plain-English verdicts.Runs in your browserAdmin utility beltRegex tester, cron explainer, Base64, JWT decoder, hashes, JSON, passwords and UUIDs. All in your browser.Runs in your browserSubnet calculatorIPv4 and IPv6 CIDR: network, range, mask and host count, plus a subnetting practice mode.
More tools
- SSL/TLS certificate checkerRuns on our serverExpiry, issuer, names and chain for a site's certificate, and the TLS version it negotiates.
- Error code lookupReferenceWhat an error code means and how to fix it: Exchange, Entra sign-in, Windows Update, printing and more.
- What's my IP?Runs on our serverYour public IP address, and who owns any public address (network, ASN, country).
- End-of-life trackerRuns on our serverWhen Windows, Windows Server, Office, SQL Server, Exchange, Ubuntu and more stop getting updates.
- Patch Tuesday hubRuns on our serverEach month's Microsoft security updates: what to patch first, the Critical fixes, and what CISA says attackers are exploiting.
- Service status boardRuns on our serverIs Microsoft 365, Azure, AWS, Google Workspace, Cloudflare, Okta, Zoom or Claude having a bad day? From their own status pages.
Tools that run in your browser never send what you type anywhere. Tools that run on our server see only what you ask them to look up, and none of it is stored: results are cached for a few minutes so repeat lookups are quick.