X509 Certificate Utility
Inspect X509 certificates inside VS Code.
Features
- X509 viewer — subject, issuer, validity, serial number, and extensions at a glance
- Chain support — multi-certificate files are displayed as a chain
- Expiry warnings — certificates expiring soon are highlighted
- Certificate Explorer — sidebar panel listing files in workspace
- Syntax highlighting — PEM blocks get colorization
Supported file types
| Extension |
Format |
.pem |
PEM (text, single or chain) |
.cer .crt |
DER or PEM certificate |
.der |
DER binary certificate |
.p7b .p7c .p7 |
PKCS#7 certificate bundle |
.crl |
Certificate Revocation List |
.csr |
Certificate Signing Request (PKCS#10) |
.p12 .pfx |
PKCS#12 keystore (certificates extracted; password prompt if protected) |
Usage
- Open a certificate file — the utility opens automatically
- Use the Certificates panel in the Explorer sidebar
- Right-click a file → X509 Certificate Utility: Open
Extension Settings
| Setting |
Default |
Description |
certview.showExpiredWarning |
true |
Highlight expired certificates |
certview.warningDaysBeforeExpiry |
30 |
Days before expiry to show warning |
certview.defaultView |
"summary" |
Default view tab |
Requirements
- VS Code 1.85 or later
- Local parsing — no network access required
Known Issues
- Large CRL files may take a moment to parse
Release Notes
0.3.0
- Added CSR (
.csr) support — Certificate Signing Request viewer (subject, public key, signature algorithm)
- Added P12/PFX (
.p12, .pfx) support — extracts and displays certificates from PKCS#12 keystores, with password prompt for protected files
0.1.4
- Improved metadata and stability
- Local certificate viewing
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