X.509 Certificate Decoder
Inspect a public PEM certificate’s subject, issuer, validity dates, fingerprints and public key without performing trust validation.
Your input is sent to this site only after you choose Convert on server. The conversion runs for this request and no history is saved. Upload up to 4 MiB combined; Office files have a 2 MiB limit.
Enter your text
Edit the example text or paste your own content.
How to use X.509 Certificate Decoder
- Load the example or paste your own input.
- Review the settings, then select Convert on server to send input for processing.
- Review the result, then copy or download it.
What this tool helps you do
Read the metadata inside one public X.509 certificate when checking a certificate export or documenting a TLS configuration. The result includes subject and issuer names, serial number, validity interval, fingerprints and the public key. The supplied example is self-signed for example.invalid and does not represent the certificate currently used by this website.
Format rules and limitations
Paste a single public CERTIFICATE PEM block only. Private keys and certificate chains are not accepted. Displaying validity dates does not establish trust: the tool does not verify a chain, hostname, revocation status or possession of the private key. Input is limited to 64 KiB and processed under the server conversion limits. Compare critical certificate information with a trusted local client before making an operational security decision.
Example input
-----BEGIN CERTIFICATE----- MIIDWTCCAkGgAwIBAgIUBZ9jz9avx7VTbL3eloKyCSYukM4wDQYJKoZIhvcNAQEL BQAwPDEYMBYGA1UEAwwPZXhhbXBsZS5pbnZhbGlkMSAwHgYDVQQKDBdDb252ZXJz aW9uIFRvb2wgRXhhbXBsZTAeFw0yNjExMDYwOTM4MzZaFw0yNzExMDYwOTM4MzZa MDwxGDAWBgNVBAMMD2V4YW1wbGUuaW52YWxpZDEgMB4GA1UECgwXQ29udmVyc2lv biBUb29sIEV4YW1wbGUwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCT bug30ZEiqF3MxzsmN3UFhaYLZq5kK2affD2OU5/m2KOlb3tb62fgjj0fnGprkQdF NR5wIFq9H1N415ZkL62ZNft9XXEiVUHi3YdjP8Rht7OwRum80+8HBtBYxyI2Opjq BdpFrT0i/Kf054RZnMMjGxUOR2+mkq/9xQqc5VtfCUZuIb+4egAUfOX2BFBSJtkC XO81wHeNlGYvsHNRVFnohQAaAWi6l1XEFhPqwS+fpXBGDEyPk2zHxDapLzUiC16X /bfIycHdPq85y3Pklm4/OmyUZv5XpnoLmIzCHZJSdiHkTT4vwofPhI34xLkTd0ZJ Ws9XrjXPCYIQHwlPonLvAgMBAAGjUzBRMB0GA1UdDgQWBBQURW51dn9Zyldmsh5F Y84DJyRK2zAfBgNVHSMEGDAWgBQURW51dn9Zyldmsh5FY84DJyRK2zAPBgNVHRMB Af8EBTADAQH/MA0GCSqGSIb3DQEBCwUAA4IBAQAJ6fcj4jhqXj6OKb03X7JLkphJ s8D71fJegsCn4RwSqJa2QVuDLk+efP/4wjdf0nmJdpb0PtDYRvKAa82Kh8W9Ahwd xNHkeuiTkXTfoUFhXTp+B9qm5kXnXa7McifZiTDk8aFqiOjnW8EbmFHlzSXvGkxo f61diWE8KoO55u0GZkZvFDUXo4fotC5J0Xhkmb+Jm9UCizRqKXDY56QTGnHV/RrQ N+KJLJOiSqISNR8ik7Zb0t5G5zOr3SGJ1mco5scaZK23zUf2KcMmW0W7WlFgX9Np TAghh5Zrmj43allGGuEAB1PKctL/eN8DLfcRLYaqboYP7qcdpg/z4Is93TG7 -----END CERTIFICATE-----
What should I check before relying on the output?
Paste a single public CERTIFICATE PEM block only.
Is input uploaded?
This tool sends input to this site’s conversion API after you select Convert on server. Files use bounded workers and, when needed, private temporary folders deleted after processing or cancellation. No conversion history is saved. The converter does not upload files to a third-party conversion service.