Your files stay on your device
X.509 certificate and CSR inspector
Paste a PEM certificate or PKCS#10 CSR and get subject, issuer, validity window, SANs, key facts, and extensions, parsed by pkijs in your tab. Nothing fetched, nothing uploaded.
- No chain validation, that needs trusted root stores and revocation data (OCSP/CRL) this offline page refuses to contact.
- “Valid now” means the validity window contains your clock. Never that anyone trusts the certificate.
- No private key handling: paste a certificate or CSR, and a CSR’s whole point is that the private key never left your machine.
Paste, drop, or type to begin. Everything stays on this device.