CSR Decoder
Paste your Certificate Signing Request (CSR) to decode all fields — subject, organization, key type, key size, and Subject Alternative Names.
100% Free
Instant Decode
SAN Validation
Paste your Certificate Signing Request
Validates FormatConfirms CSR is parseable
Key InfoType, algorithm, and bits
SAN CheckWarns if SANs are missing
All FieldsSubject + org information
Secure by designYour CSR data is processed instantly over an encrypted connection and never stored on our servers.
Encrypted in transitSubmitted over HTTPS/TLS — nothing is sent in plain text.
Never storedDecoded CSR data is not saved to any database or log.
No third-party sharingYour CSR contents are never shared with ads, trackers, or outside services.
Processed instantlyParsed on request and discarded immediately after the response.
About CSR Decoder
What Is a CSR Decoder?
A CSR decoder reads a Certificate Signing Request's encoded content and translates it into human-readable fields — domain, organization, country, and public key details — useful for verifying a CSR you received from someone else or double-checking your own before submission.
How to Use the CSR Decoder
- Paste the CSR text
- Click Decode
- Review the readable output
Key Features
- Complete field breakdown — every encoded detail shown clearly
- Fast verification — no need for command-line OpenSSL tools
Who Uses This Tool
System administrators and developers verify CSR contents without needing command-line tools.
Frequently Asked Questions
Is this different from the CSR Checker tool?
Both decode CSR contents — use whichever workflow fits your process, the underlying result is the same readable breakdown.
Is this tool free?
Yes, decoding a CSR is completely free.
Frequently Asked Questions
What is a CSR?
A CSR (Certificate Signing Request) is a block of encoded data you send to a Certificate Authority (CA) when applying for an SSL certificate. It contains your public key and organization details. The CA validates and signs it to produce your SSL certificate.
Why are SANs important in a CSR?
Since Chrome 58 in 2017, browsers only trust certificates based on their SAN (Subject Alternative Name) fields — the Common Name (CN) is ignored for matching. A CSR without SANs will produce a certificate that modern browsers will reject or warn about.
What key size is recommended?
RSA 2048 is the minimum accepted by major CAs and is considered safe. RSA 4096 is stronger but slower. ECC P-256 provides equivalent security to RSA 3072 with a much smaller key, making it ideal for performance-conscious servers.
Can I use the same CSR for renewal?
Yes, you can — but it's not recommended. Reusing a CSR means reusing the same private key. Security best practice is to generate a new private key and CSR each time you renew to limit exposure from any past key compromise.
Related Tools
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