An MX record tells other mail servers where to deliver email for your domain. Each MX has a priority; lower numbers are tried first.
When someone emails you@example.com, the sending server looks up the MX records for example.com and connects to the host with the lowest priority value. Providers like Google Workspace and Microsoft 365 publish several MX hosts at different priorities so mail keeps flowing even if one server is unavailable. Getting these records exactly right matters more than almost any other DNS change, because a mistake means lost or bounced email rather than a slow web page.
After you switch email providers, senders around the world will keep using your old MX records until their cached copies expire, so mail can briefly arrive at both the old and new hosts. This checker queries your MX records from many vantage points, letting you confirm every location now lists the new mail servers and correct priorities before you decommission the old inbox. If some resolvers still return the previous provider's hosts, wait for the TTL to elapse. Pair this check with SPF, DKIM, and DMARC (a TXT record) to keep your mail deliverable.
Frequently asked questions
- What does MX priority mean?
- Sending servers try the lowest priority number first. Equal priorities are load-balanced.
- How long until new MX records take effect?
- Up to the record's TTL, commonly a few hours. Until then, some senders may still use the old servers.