DecodeEncode
SSL/PEM Certificate Decoder
Utility Workspace

SSL/PEM Certificate Decoder

Decode and inspect X.509 certificates

Client-sideX.509 / PEMInstant
Tool Guide

What is a PEM Certificate?

A PEM (Privacy Enhanced Mail) certificate is a Base64-encoded X.509 certificate enclosed between -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- headers. It is the most common format for SSL/TLS certificates used to secure websites and services.
Practical Flow

How to Use This Tool

  1. 1
    Paste Your Certificate: Copy your PEM-encoded certificate and paste it into the input area.
  2. 2
    Click Decode: Press the "Decode Certificate" button to parse and inspect the certificate.
  3. 3
    View Details: See the subject, issuer, validity dates, serial number, signature algorithm, public key info, and expiry status.
  4. 4
    Copy JSON: Click "Copy JSON" to copy all decoded details as a JSON object.
Keep In Mind

Important Note

All parsing is done entirely in your browser. Your certificate data never leaves your device. We use the open-source node-forge library for X.509 parsing.
More Details

What Information is Decoded?

  • Subject: The entity the certificate is issued to.
  • Issuer: The Certificate Authority that signed the certificate.
  • Validity: The date range during which the certificate is valid.
  • Serial Number: A unique identifier assigned by the CA.
  • Signature Algorithm: The algorithm used to sign the certificate (e.g., SHA-256 with RSA).
  • Public Key: The type and size of the public key (e.g., RSA 2048-bit).
  • SANs: Subject Alternative Names — additional domains covered by the certificate.

Explore More

JWT DecodeInspect and verify JSON Web Token payloads and headers.
UUID GeneratorGenerate UUID/GUID v1, v4, and v5 identifiers instantly.
Hash GeneratorGenerate MD5, SHA-1, SHA-256, SHA-512 hashes from any text.
SAML DecoderDecode Base64-encoded SAML responses and inspect XML.
Base64 EncodeConvert plain text or binary data into Base64 format instantly.
Base64 DecodeDecode Base64 strings back to readable text or binary data.
URL Encode/DecodeEncode or decode URLs, query strings and special characters.
Base64 ImageConvert images to Base64 strings and decode Base64 back to images.