How to use this tool
- Enter your values or try the example.
- Run the tool and check the result.
- Save the result where a download is available.
Supported features & limits
Accepts PEM-encoded PKCS#10 requests with RSA keys. Shows subject, requested domains and signature verification. A valid signature does not prove domain ownership. No private key is needed. Maximum 100 KB.
What happens to my files?
Your browser reads the file locally. File contents are not sent to our server. Closing or resetting this page clears the working result. Downloaded copies remain on your device.
Maintained by Roman Zmazhenko. Updated 1 November 2026.