SSL Certificate & CSR Decoder
Decode X.509 certificates and PKCS#10 CSRs pasted as PEM text, right in your browser.
How to Decode an SSL Certificate or CSR for Free & Privately
1. Open your .crt/.pem certificate file or .csr request file in a text editor.
2. Copy the entire PEM block, including the BEGIN/END lines.
3. Paste it into the box on the left — decoding happens instantly as you type.
4. Review the Subject, Issuer, validity, fingerprint, and full ASN.1 details on the right.
Decode Certificates Safely, Fully Client-Side
Parsing the certificate or CSR is handled entirely via browser technology (WebCrypto). The PEM text you paste is never uploaded to any server.