SSL Certificate Decoder
Decode and inspect SSL/TLS certificates. Paste a PEM or CRT file to extract domain, issuer, expiry date, SANs, and fingerprints — entirely in your browser.
Free Runs in your browser Web Tools
How to use
- 1 Paste a PEM-encoded certificate (beginning with -----BEGIN CERTIFICATE-----) into the textarea.
- 2 Click Decode — the certificate fields are extracted entirely in your browser.
- 3 Review the subject, issuer, validity dates, SANs (Subject Alternative Names), and key details.
- 4 No certificate data is sent to any server — the entire parsing happens client-side.
Key features
- Decodes PEM certificates entirely in your browser — no data sent to any server
- Shows validity period, issuer, subject, and all SANs (Subject Alternative Names)
- Highlights expired or about-to-expire certificates
- Useful for debugging TLS issues and certificate renewals