Certificate Decoder (X.509)
Read the details of an X.509 certificate.
Runs in your browser: what you paste is never uploaded
How to use Certificate Decoder (X.509)
- 1Paste or type your inputUse the box above, or click Sample to try it with an example.
- 2Choose your optionsPaste a PEM certificate or open a .pem, .crt, .cer or .der file.
- 3Copy the resultCopy it with one click. Nothing is sent anywhere.
About Certificate Decoder (X.509)
Decode an X.509 SSL/TLS certificate to see its subject, issuer, validity dates, key, SANs, extensions and fingerprints.
Frequently asked questions
Is it safe to paste a certificate here?
Certificates are public, and this one is decoded in your browser without being sent anywhere. Never paste a private key into any website.
Does it check the certificate chain?
No. It shows what's in the certificate, including whether it's expired or self-signed, but doesn't verify it against trusted roots.
Is what I paste sent anywhere?
No. The tool runs entirely in your browser and never sends what you type or paste to a server.
Is it free?
Yes. It's free, with no sign-up and no limits.
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