PEM Certificate & JWK Inspector
Inspect X.509 PEM certificates and JSON Web Keys locally — subject, issuer, SANs, expiry, and key type without uploading.
Batch workspace
Format multiple files locally in one run.
How to use the Certificate & JWK Inspector
Paste code or file
Paste your raw TEXT text or upload directly.
Configure options
Choose indentation, dialect, or formatting preferences.
Format & export
Click format, then copy, download, or inspect in tree view.
What is a Certificate & JWK Inspector?
Inspect X.509 PEM certificates and JSON Web Keys locally — subject, issuer, SANs, expiry, and key type without uploading. This tool re-indents and organizes code according to standard style conventions while checking for syntax validity. Everything executes 100% inside your browser, guaranteeing zero latency and complete privacy for API keys, user tokens, and confidential database schemas.
Frequently Asked Questions
Does this tool upload my private keys?
No. Parsing runs entirely in your browser. Prefer public certificates and public JWKs; never paste production private keys into any online tool.
What formats are supported?
PEM CERTIFICATE / PUBLIC KEY blocks and JWK or JWKS JSON documents.
Can I see Subject Alternative Names?
Yes. DNS SANs are extracted from the X.509 subjectAltName extension when present.
How is the fingerprint calculated?
SHA-256 over the DER bytes of the PEM payload, shown as colon-separated hex.
Will malformed PEMs show helpful errors?
Yes. Invalid base64, missing BEGIN/END markers, and non-JWK JSON return plain-English errors.