CSR Generator

Generate Certificate Signing Requests (CSR) for SSL/TLS certificates with custom subject information and key parameters.

Overview

This CSR generator creates a Certificate Signing Request and matching RSA private key directly in your browser using the Web Crypto API — nothing is sent to any server. Fill in your subject information (Common Name, organization, country), choose a key size of 2048 or 4096 bits, and download a PEM-formatted CSR ready to submit to any Certificate Authority. Because the private key is generated and stays entirely on your device, there is no risk of it being intercepted in transit or stored on a third-party server — a critical guarantee for any production SSL/TLS credential.

Common Use Cases

  • Domain SSL Certificate — Prepare a CSR for a public-facing website to submit to a CA such as DigiCert, Sectigo, or Let's Encrypt.
  • Wildcard Certificate Request — Generate a CSR with a wildcard Common Name (*.example.com) to secure all subdomains under a single certificate.
  • Internal PKI Enrollment — Create certificate signing requests for internal services against a self-hosted or enterprise CA without exposing private key material to online tools.
  • Multi-Domain SAN Certificate — Set up the base CSR for a Subject Alternative Name certificate covering multiple hostnames or services.
  • Certificate Renewal Prep — Quickly generate a fresh private key and CSR before an existing SSL certificate expires, following the best practice of never reusing a private key.

How It Works
1

Enter Certificate Details

Fill in subject information including common name (domain), organization, country, and other certificate fields.

2

Configure Key Parameters

Choose key size (2048, 4096 bits) and algorithm. The tool generates a new private key automatically.

3

Generate CSR and Key

Download the generated CSR file to submit to a Certificate Authority and securely store the private key.

Frequently Asked Questions

What is a CSR and why do I need one?
A Certificate Signing Request (CSR) contains your public key and identity information. You submit it to a Certificate Authority (CA) to get an SSL certificate issued for your domain or organization.

What should I put in the Common Name field?
The Common Name should be the fully qualified domain name (FQDN) for your website, like 'www.example.com' or 'example.com'. For wildcard certificates, use '*.example.com'.

What happens to the private key?
The tool generates a new private key along with the CSR. You must download and securely store this private key - you'll need it when installing the issued certificate.

Which key size should I choose?
2048-bit keys are standard and widely supported. 4096-bit keys offer more security but may have performance impacts. Most CAs recommend 2048-bit for web certificates.

Is the CSR generation secure?
Yes, all key generation and CSR creation happens locally in your browser using cryptographically secure random number generation. Nothing is transmitted to external servers.

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