How it works
Complete the job in three clear steps
- Paste a PEM certificate or chain, or choose a PEM/DER certificate file.
- Inspect the parsed fields and locally calculated results.
- Copy or download the JSON report for review.
Private X.509 certificate tool
X.509 Certificate Decoder
Decode PEM or DER X.509 certificates into subjects, issuers, validity dates, algorithms, extensions, SAN entries, and fingerprints.
Free to use Certificate bytes are parsed in this browser and are never sent to Lucaden.
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Important
Check the result before relying on it
Scan-test generated codes before printing or distribution. A generated barcode does not register identifier ownership, and decoded external links should be checked before opening.
Practical details
What this Lucaden tool does
Decode PEM or DER X.509 certificates into subjects, issuers, validity dates, algorithms, extensions, SAN entries, and fingerprints.
Peculiar X.509 supplies standards-aware ASN.1 parsing. Lucaden adds focused reports and makes the limits of offline inspection explicit.
Included capabilities
- PEM and binary DER input
- Subject and issuer fields
- SAN and extension inventory
- Downloadable JSON report
Useful for
- Inspect a TLS certificate
- Review an internal CA certificate
- Debug certificate metadata
- Document a certificate fixture
Questions
About this tool
Does this prove a certificate is trusted by my browser?
No. Local parsing and signature checks do not consult an operating-system trust store, hostname policy, revocation service, OCSP, or certificate transparency logs.
Can I inspect a private internal certificate?
Yes. Certificate bytes stay on this device, but avoid pasting a private key because none is needed for these tools.
Open-source foundations
Built transparently
Lucaden documents its standards sources, architectural references, and permissive runtime dependencies while keeping this workspace consistent with the Lucaden interface.