Cómo usar: CSR Decoder
- Paste the CSR (
-----BEGIN CERTIFICATE REQUEST-----) or open the.csrfile. - Check the Common Name and the Subject Alternative Names — every domain you need must be listed.
- Confirm the key type and size (RSA 2048+ or EC P-256/P-384).
What is a CSR?
A Certificate Signing Request (PKCS#10) is what you send to a certificate authority to get a TLS certificate. It contains your public key, the identity you want in the certificate and any requested extensions such as Subject Alternative Names, all signed with your private key to prove you hold it. The private key itself never leaves your server.
Checklist before submitting
- Domains: every hostname — including
wwwand bare domain — must appear in the SAN list. Many CAs copy the CN into the SANs, but not all. - Key: RSA 2048 bits or more, or ECDSA P-256 / P-384. Smaller RSA keys are rejected.
- Organization fields: for OV/EV certificates, O, L, ST and C must match your legal registration exactly. For DV certificates they are ignored.
- Signature: SHA-256 or better.
Creating a CSR with OpenSSL
openssl req -new -newkey rsa:2048 -nodes \
-keyout example.key -out example.csr \
-subj "/CN=example.com" \
-addext "subjectAltName=DNS:example.com,DNS:www.example.com"Keep example.key secret and on the server. After the CA issues the certificate, decode it with the certificate decoder and check the live site with the SSL checker.
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Herramientas que combinan con: CSR Decoder
- RSA Key Generator — Create a public/private key pair for JWT signing, TLS testing, encryption experiments or SSH — generated by your browser’s Web Crypto API and never sent anywhere.
- SSH Key Generator — Create an SSH key pair for GitHub, GitLab, servers or CI deploy keys — Ed25519 by default, in standard OpenSSH format, without installing anything.
- DNS Lookup — Query all common DNS record types for a domain in one go, with TTLs, sorted MX records and an SPF/DMARC email-authentication summary.
- Decodificador JWT — Pega un token web JSON para examinar su encabezado y su carga útil, comprobar cuándo caduca y verificar su firma.
Preguntas frecuentes
Does a CSR contain my private key?
No. It contains only the public key and is safe to share with the certificate authority. Keep the private key on your server.
Why are my extra domains missing?
They must be requested as Subject Alternative Names. Recreate the CSR with
-addext "subjectAltName=DNS:…" or the SAN field in your control panel.Is my CSR uploaded?
No. It is decoded in your browser.
¿Puedo instalar CSR Decoder como aplicación web y utilizarla sin conexión?
Sí. CSR Decoder es una aplicación web instalable (PWA): se instala desde el navegador, no se descarga desde una tienda de aplicaciones. Haz clic en «Instalar aplicación» en la parte superior de esta página en Chrome o Edge (Windows, macOS, Linux, ChromeOS) o, en Android, utiliza «Compartir» → «Añadir a la pantalla de inicio» en iPhone y iPad, o «Archivo» → «Añadir al Dock» en Safari 17+ en un Mac. A continuación, se abrirá en su propia ventana con su propio icono y, como se ejecuta íntegramente en tu navegador, seguirá funcionando sin conexión. Firefox en el ordenador de sobremesa no permite instalar aplicaciones web. Cómo funciona la instalación.