How to use DKIM public key inspector
Inspect a pasted DKIM key record, its key type, flags and public-key size. The check runs when you submit the form. Its inputs are processed in this browser.
How the check works
The tool decodes the p tag. RSA keys are imported as SubjectPublicKeyInfo through Web Crypto to read their modulus size; Ed25519 keys are checked for a 32-byte public value.
The Overview tab explains the findings. Measured data lets you search individual fields and values, while JSON report shows the complete export. Export JSON to retain a baseline, or print the findings for your own records. Review the report before sharing it: browser characteristics, token claims, and file names can reveal information about your setup.
Read the result in context
An empty p tag indicates a revoked key. Key size, test flags and declared algorithms are useful configuration evidence, but they do not validate a message signature.
Understand the limits
Only public keys belong here. The tool does not request selectors from DNS or implement DKIM message canonicalisation and signature verification.
Common questions
Where is the input processed?
In this browser tab. This tool does not submit its input to the site server or a third-party service.
What should I keep with a result?
Record the selected options, browser and time. Review exported values before sharing them. Generated passwords, tokens and HMAC secret keys are excluded from report exports.