Certificate Decoder
Decode a PEM/DER certificate into human-readable fields. Paste your data, then click to dissect it. Everything runs on your device, nothing is sent to a server.
Everything runs in your browser. Your data is never sent to our servers.
Example
Example Input
-----BEGIN CERTIFICATE-----…
Example Output
Parsed certificate fields
How to Use
- 1Paste your data (PEM/Base64/token) into the Input field.
- 2Click the button (or press Ctrl+Enter) to dissect it.
- 3Read the decoded result in the Output field.
About Certificate Decoder
Certificate Decoder turns a certificate that looks like a Base64 blob into clear, readable fields: who it was issued to, by whom, and when it is valid.
It is useful when inspecting a CA-issued certificate, debugging TLS issues, or verifying a certificate chain. It supports PEM and Base64 DER input.
This decoder works locally in the browser. For raw ASN.1 structure inspection, see the ASN.1 Inspector; for validity only, see the Certificate Expiration Checker.
FAQ
Are my data or keys sent to a server?
No. Certificate Decoder runs entirely in your browser using the Web Crypto API and client-side libraries. Your data, passwords, and keys never leave your device.