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SSL Certificate Decoder

Decode and view SSL certificate details including subject, issuer, and validity period. Code never leaves your device — formatting and validation run locally in your browser.

100% Local Browser Native

How to Use the SSL Certificate Decoder

1. Paste source for SSL Certificate Decoder

Paste source for SSL Certificate Decoder into the input area. Nothing runs until you trigger it.

2. Decode

Decode back to readable form.

3. Copy decoded

Copy the decoded output.

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Frequently Asked Questions

PEM input?

Paste one PEM certificate at a time — chains decode first-certificate-only.

Expiry shown?

Not-before/not-after dates exactly as encoded. No days-remaining math — compare against today yourself.

Chain order?

Single-certificate view only — paste each chain member separately; truncated sample blobs fail with an honest error.

Is my input uploaded anywhere when using SSL Certificate Decoder?

No — decoding runs locally in your browser, free with no signup.

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Last updated October 2026