Tools
Small tools for the checks we run most.
Each tool runs entirely in your browser, needs no account, and explains its result next to the relevant guide. The DNS lookup sends queries directly to Cloudflare and Google; the others make no network requests at all.
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DNS Lookup & Resolver Comparison
Query any hostname through Cloudflare and Google DNS-over-HTTPS side by side and compare answers, TTLs, and DNSSEC status.
Use it after changing a record, to see whether two major public resolvers already return the new value.
Open the tool -
Hostname & Subdomain Checker
Validate a hostname against DNS label rules, spot risky or reserved labels, and see which wildcard certificates would cover it.
Use it before you create a subdomain, or when a platform rejects a name and you want to know why.
Open the tool -
TTL Cutover Planner
Turn your current TTL and planned change time into a dated timeline for lowering the TTL, switching the record, and raising it again.
Use it before a migration, to know when to lower the TTL and how long to keep the old server running.
Open the tool -
CAA Record Generator
Build CAA records for the certificate authorities you actually use, including wildcard policy and incident reporting.
Use it when you want only your chosen certificate authorities to be able to issue for your domain.
Open the tool
Why these tools exist
They automate the steps our guides ask you to do by hand: compare resolvers instead of trusting one answer, check a name before publishing it, schedule a TTL change instead of guessing, and write CAA records without looking up each CA's identifier. If a result surprises you, the guide linked from each tool explains what is going on.
Something missing or wrong? Tell us at admin@and.guide.