What tools check SPF records?

You need to validate your SPF record, but you're not sure which tool to reach for. The good news: there are several solid options, and they all do basically the same job. Pick based on what you're most comfortable with.

Web-based validators (easiest start)

MXToolbox SPF Lookup is the most popular choice. You paste your domain, and it'll check your SPF syntax, count your DNS lookups, and flag any obvious problems. Kitterman SPF Validator does similar work but adds more detail on each lookup it finds. If you want a visual representation of how your includes expand, dmarcian's SPF Surveyor shows a tree diagram of your entire lookup chain.

Command line (if you're comfortable with terminal)

You can also run dig TXT yourdomain.com directly. This shows your raw SPF record without any interpretation, which is useful if you want to see exactly what's published without a tool's interface in between. It's faster once you get used to it, but it requires reading the output correctly.

What all these tools check

But every validator looks for syntax validity, counts your DNS lookups against the 10-lookup limit, expands nested includes so you can see what's really happening, and flags policy completeness issues. Most also warn you if you're close to limits even if you haven't hit them yet.

Next step: pick one and run it

Run validation after any SPF change to catch errors before they affect your mail. If you want quick feedback without leaving your browser, start with MXToolbox. If you're more technical and want the most detailed output, use Kitterman. Once you've run your validation, save your results so you've got a baseline to compare against in the future. Not sure what the results mean? We've got a free guide to reading DNS results and our SOS hotline can walk you through interpreting what you're seeing if you get stuck.