CSR Decoder and Validator
Paste a certificate signing request in PEM form and check its basic structure.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
CSR Decoder and Validator
How to use this tool
- Enter your values in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.
Worked example
Pasting a short PEM block decodes it and reports its byte size and whether a DER sequence starts it.
What this tool does not do / Limits
This tool performs a basic structure check only. It is not full ASN.1 parsing, signature validation, or a certificate-authority check.
Frequently asked questions
Does a plausible result mean my CSR is valid?
No. It only checks basic structure; full validation needs a proper CSR parser and signature check.
Is my CSR uploaded anywhere?
No. Decoding runs entirely in your browser.
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