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Inspect certs and keys without leaving the browser.
Paste this into any page — the live tool appears with a credit link back here.
Paste a PEM certificate or RSA public key to parse the subject, issuer, validity, and key info.
🔒 This tool runs entirely in your browser. Nothing is uploaded or stored.

Background reading: Pem Decoder on Wikipedia. More: all developer tools.
Open the PEM Certificate & RSA Key Decoder and use the controls in the workspace below: inspect certs and keys without leaving the browser. Results appear instantly in your browser, with nothing to install, sign up for, or pay for.
Yes. The PEM Certificate & RSA Key Decoder is completely free, like every tool in the PrimeFreeTools library. There are no accounts, subscriptions, or usage limits.
No. The PEM Certificate & RSA Key Decoder runs with JavaScript in your browser, so what you enter never leaves your device and nothing is stored on a server.
Paste a PEM certificate or RSA public key to parse the subject, issuer, validity, and key info. You will find it grouped under Developer Tools together with 78 other free tools on the PrimeFreeTools homepage.
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Sep 7, 2026
Inspect certs and keys without leaving the browser.
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