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PEM / Certificate Decoder

System ideaMissing a tool?

Inspect PEM blocks and validate base64 locally

Paste a PEM certificate or key block, identify its envelope type, validate the base64 payload and see decoded byte counts without uploading anything.

Output
PEM type: CERTIFICATE
Base64 length: 247
Decoded bytes: 185

This browser-only decoder identifies the PEM envelope and validates the base64 payload. It does not call an online certificate parser.
CategoryCERTIFICATELength247Decoded bytes185

Everything on this page is processed in your browser. Nothing is uploaded.

Everything on this page is processed in your browser. Nothing is uploaded.

What this tool does

This tool checks the BEGIN and END envelope, strips PEM line wrapping, validates the base64 body and reports the decoded size. It is useful for quick sanity checks before pasting material into OpenSSL or a certificate manager.

How to use it

  1. Paste a PEM certificate, public key or private key block.
  2. Review the detected type, encoded length and decoded byte count.
  3. Copy the summary for a support ticket or deployment note.

Privacy

This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.

Frequently asked questions

Does this upload my certificate?
No. The PEM text is parsed in your browser tab only.
Does it fully parse X.509 fields?
No. This version validates the PEM wrapper and base64 payload; it does not decode every ASN.1 certificate field.
Can I paste private keys?
The tool runs locally, but you should still avoid sharing private keys in screenshots or support messages.

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