PEM Certificate Inspector
Parse a PEM certificate or private key and inspect its fields
About
Parse a PEM-encoded X.509 certificate or private key and show its fields: subject and issuer DNs, validity window (with expired status), serial number, version, public-key algorithm and size, signature algorithm, and Subject Alternative Names. Everything runs locally in your browser; the PEM is never uploaded.
About this tool
Paste a PEM certificate or private key and inspect subject, issuer, validity, serial, public-key size and SANs. 100% local. Free, no signup. PEM Certificate Inspector runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- PEM Certificate Inspector is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use PEM Certificate Inspector?
Open PEM Certificate Inspector, enter or paste your input, and copy the result. The page works without an account.
Related guides
PKI Key Pair Generator: Self-Signed Certs and CSRs in the Browser
Generate RSA/ECDSA keys, self-signed X.509 certificates and PKCS#10 CSRs online with node-forge — for local HTTPS and dev TLS.
Reading a PEM Certificate: Subject, Issuer, SANs and Expiry
What the fields in a PEM certificate mean, why Subject Alternative Names matter more than the Common Name, and how to decode expiry and key usage.
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