PEM Decoder

Paste a PEM certificate, CSR, or key. See type, subject, SAN, dates, and issuer. Decode runs in the browser. No network scan.

Reviewed by Olgun Ozoktas

The PEM stays in your browser. This tool does not scan hosts. Analytics and ads may load on the page.

Paste one or more PEM blocks. Private key bytes are not printed.

How to decode a PEM

  1. 1

    Paste PEM

    Include the BEGIN and END lines.
  2. 2

    Decode

    Read type, subject, SAN, and dates when the parser can extract them.
  3. 3

    Read keys with care

    For PRIVATE KEY blocks, only type, length, and algorithm appear.
  4. 4

    Use the sample

    Load sample produces a local certificate with CN=localhost.

Why decode PEM in the browser

A PEM block is base64 DER between BEGIN and END labels. This page splits those blocks, measures DER length, and walks X.509 enough to show subject, issuer, dates, and SAN when the structure is a certificate. Private key material is not printed. The PEM is not uploaded to FindUtils. Analytics or ads on the page may still load.

Frequently Asked Questions

1

Does this contact a CA?

No. Decode is local. Analytics and ads may still load on the page.
2

Can it decode a private key?

It shows the PEM type and length. It does not print key bytes or send the key anywhere.
3

Is this a live SSL check?

No. Use the SSL checker for a live URL.
4

What if subject is missing?

Some PEMs only show type and length if the ASN.1 walk cannot read names.
5

Does it verify the chain?

No. It inspects the pasted block.

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