Online CSR Generator – Create CSR & Private Key

Generate Certificate Signing Requests (CSR), RSA/ECC private keys, wildcard CSR, and SAN CSR entirely inside your browser. No uploads, no logging, no data storage — fully secure and offline.

CSR Details

The primary domain (required). For wildcard use *.example.com in SAN.
Optional. Comma-separated. Supports wildcards. If left empty CSR will contain only CN.
Note: Everything happens in your browser. Private key never leaves your device unless you download or copy it.
Private Key
CSR (Certificate Signing Request)
Entropy: —

How to use

  1. Enter CN and optional SANs (comma separated). For wildcard use *.example.com in SAN.
  2. Choose key type and size. Click Generate.
  3. Save private key securely. Upload CSR to your Certificate Authority to get a signed certificate.

Why Use Our CSR Generator?

  • 100% offline CSR and private key generation — nothing uploaded to any server
  • Supports RSA 2048/4096 and ECC P-256/P-384
  • Create SAN and wildcard CSRs for complex SSL setups
  • Instant ZIP download containing CSR + private key
  • Secure cryptography using PKI.js & browser-based entropy

About This CSR Generator

This CSR Generator allows you to create Certificate Signing Requests and Private Keys entirely inside your browser. No information is uploaded, ensuring maximum privacy and security for SSL certificates, HTTPS websites, and domain validation.

CSR Generation Best Practices

Generating a CSR correctly is critical for a smooth SSL certificate issuance process. Small mistakes at this stage can lead to rejected requests, incorrect certificates, or the need for reissuance. Always ensure that the Common Name (CN) and SAN entries accurately reflect all domains that will be served over HTTPS.

For modern browsers, SAN fields are mandatory. Relying only on the Common Name may result in browser warnings. When choosing key types, RSA 2048 is widely supported, while RSA 4096 and ECC keys provide stronger security at the cost of slightly higher computational requirements.

Once generated, private keys should be stored securely and backed up safely. Losing the private key will require generating a new CSR and reissuing the certificate.

CSR Generation in Real Deployment Workflows

In real-world environments, CSR generation is often part of a larger deployment workflow that includes certificate issuance, installation, and renewal. System administrators typically generate CSRs during initial server setup, domain onboarding, or certificate renewals.

For cloud platforms, load balancers, and containerized environments, CSRs are generated before integrating certificates into automation pipelines. Validating CSR details early helps prevent downtime caused by incorrect domain coverage or incompatible cryptographic settings.

Because this tool operates entirely in the browser, it can be safely used in restricted networks where uploading private keys or CSR data is not permitted.

Proper CSR generation is a foundational step in maintaining secure and trusted HTTPS services.

Choosing Between RSA and ECC Keys

RSA and ECC are both widely supported key algorithms, but they serve slightly different needs. RSA 2048 remains the industry standard due to its compatibility with older systems and devices. RSA 4096 offers stronger security but may introduce minor performance overhead on high-traffic servers.

ECC keys, such as P-256 and P-384, provide equivalent or stronger security with smaller key sizes. This makes them efficient for modern environments, including mobile applications, APIs, and cloud load balancers. However, ECC support should always be verified when dealing with legacy clients or embedded systems.

Supported Key Types

  • RSA – 2048 / 4096 bit
  • ECC – P-256 and P-384 curves

What You Can Generate

  • CSR (Certificate Signing Request)
  • RSA or ECC Private Key
  • ZIP archive containing CSR and private key
  • CSR with SAN (Subject Alternative Names)

Use Cases

  • SSL Certificates (DV / OV / EV)
  • Wildcard certificates
  • Multi-domain / SAN certificates
  • HTTPS for websites, servers, APIs

Common CSR Mistakes to Avoid

  • Including wildcard domains in CN — Wildcards should always be placed in SAN, not the Common Name.
  • Forgetting SAN entries — Browsers ignore CN when SAN is missing, leading to certificate warnings.
  • Using incorrect country codes — Country (C) must always be a valid two-letter ISO code.
  • Losing the private key — Without the private key, certificates cannot be installed and must be reissued.

Reviewing CSR details carefully before submission helps avoid certificate reissues and production downtime.

These best practices are commonly followed by hosting providers and enterprise IT teams.

Related SSL Tools

SSL Checker · CSR Decoder · SSL Tools Home

Frequently Asked Questions

Yes. All key generation happens locally in your browser. Nothing is uploaded or stored on any server.

No. Your private key never leaves your device. You are the only one who can download or copy it.

Yes. You can generate wildcard (e.g., *.example.com) and SAN (multiple domain) CSRs easily.

Supported types: RSA 2048/4096 and ECC P-256 / P-384 curves.
Trusted by developers, sysadmins and hosting providers for secure CSR generation.
Security Tips
  • Never share your private key.
  • Store private keys offline or in a secure vault.
  • Use DNS-01 validation for wildcard certificates.