Certificate Decoder, Checker & Converter
Paste or drop any certificate, chain, CSR or key — see expiry, names and fingerprints, verify the chain and convert formats.
Help shape Certificate Decoder, Checker & Converter
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Frequently Asked Questions
Everything is decoded with JavaScript in your tab — nothing is uploaded, logged or saved, and pasted private keys are never stored in the browser. For production keys, you can also disconnect from the internet first.
Paste both. The certificate shows a Key matches badge when the private key's public half equals the certificate's public key.
Servers must send the leaf certificate first, then each issuer. The chain panel reorders it and lets you download a correct fullchain.pem.
Yes. Drop it, enter the password, and the certificates and private key inside are decoded and can be exported as PEM.
It's the base64 SHA-256 hash of the public key, used for certificate pinning in apps and HPKP-style configs. It stays the same when you renew with the same key.