MTA-STS Checker
Check a pasted MTA-STS policy for mode, hosts and max-age.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
MTA-STS Checker
How to use this tool
- Enter your values in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.
Worked example
Policy with mode enforce, one mail host and max_age 86400 gives mode enforce, 1 host and 1 day.
What this tool does not do / Limits
This tool only reads the policy text you paste. It does not fetch a policy from a domain, does not check DNS records and does not verify that a mail server enforces the policy.
Frequently asked questions
Does this check my domain live?
No. It only analyses the text you paste here. Nothing is fetched from your domain or any mail server.
What does enforce mean here?
It is the mode value written in the pasted policy. This tool reports what the text says; it does not prove a server follows it.
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