What online tools can I use to check my MX records?

Your MX records tell the internet where to deliver email sent to your domain. If they're wrong, missing, or pointing to the wrong server, inbound mail fails silently. So before you blame your ESP or your DNS provider, checking your MX records takes about ten seconds.

Here are the tools that do the job well.

Online tools

MXToolbox MX Lookup is the most commonly used. It shows your MX records, the priority values for each, and whether the mail servers are actually reachable. It also flags obvious configuration problems, which is handy if you're not sure what you're looking at.

Google Admin Toolbox Dig runs a clean DNS query directly from Google's infrastructure. It's less opinionated than MXToolbox (no color-coded warnings), but it's fast and reliable for a quick raw lookup.

DNSChecker is useful when you want to confirm propagation across multiple locations. It queries from servers around the world simultaneously, so you can see if your records are consistent globally or if some regions are still seeing old data after a recent change.

Command line (if you prefer it)

If you're comfortable with a terminal, these two commands give you the same information without leaving your screen.

dig MX yourdomain.com
nslookup -type=MX yourdomain.com

What to actually check

And once you have the results, here's what to look at. Are the right mail servers listed? Are the priority numbers correct (lower number means higher priority)? Do the servers actually respond to connections? And if you just made a DNS change, do results look consistent across different locations?

It's worth running a check any time you switch email providers, migrate to a new mail server, or start troubleshooting why someone says they're not getting your email. (It's one of the first things to rule out.)

If MX is only part of what you're diagnosing, you might also want to check your SPF record and DMARC record at the same time. DNS issues rarely travel alone.