DNS Propagation Checker
Query a domain's DNS records against multiple public resolvers (Google, Cloudflare, and more) at once to see whether a nameserver or record change has propagated worldwide yet.
Tips
- Right after changing a nameserver or A record, some resolvers may still return the old value until their cached TTL (Time To Live) expires — that's expected, not a bug.
- If resolvers disagree, check the TTL first. A longer TTL (e.g. 24 hours) means propagation naturally takes longer to complete everywhere.
- This tool isn't limited to A records — use it for MX and TXT (SPF/DKIM, etc.) too, especially right after changing email-related settings.
- An NXDOMAIN response means the domain itself doesn't exist. Double-check for typos or an expired registration.
- Because this tool queries resolvers operated outside Japan as well, it's also useful for gauging propagation status for an international audience.
Frequently asked questions
Side Note — nobody actually "broadcasts" DNS changes
DNS has relied on hierarchical caching since it was first designed in 1983. If every resolver on earth had to walk all the way back to the root servers for every single query, the system simply couldn't keep up — so each resolver keeps an answer in its own cache for as long as the record's TTL (Time To Live) allows, answering repeat questions instantly from that cache. This is exactly what makes DNS fast, but it also creates a side effect: a delay before a change is visible everywhere.
That delay is commonly called "DNS propagation," but nothing is actively being broadcast to the world. What really happens is that each resolver's stale cache entry quietly expires on its own TTL schedule, and only gets refreshed the next time someone happens to query it — a slow, passive turnover rather than a push. Set a 24-hour TTL, and in theory some resolver somewhere could keep serving the old value for the full 24 hours after your change.
The DoH (DNS over HTTPS) protocol this tool relies on was originally pushed forward around 2018 by Mozilla and Google, largely for privacy reasons — so that ISPs and other parties on the network path couldn't see the contents of a DNS query. Encrypting DNS traffic inside ordinary HTTPS had a useful side effect too: it gave rise to a standardized JSON API that tools like this one can use to query multiple public resolvers through a server, without needing raw DNS sockets.