How This CSR Generator Works
Fill in your domain and organization details, pick RSA or ECDSA, and this csr generator online produces a matching private key plus a standard PKCS#10 CSR in PEM format, ready to submit to a certificate authority. Whether you call it a certificate signing request generator or just a csr generator, every step, key generation and CSR signing alike, runs in your browser via the Web Crypto API, so this is a genuine generate csr online free workflow with nothing round-tripping to a server.
RSA vs ECDSA: Which Key Type Should You Choose?
RSA is the long-standing default, universally supported by every certificate authority and every client going back decades, 2048-bit RSA is the safe, compatible choice for almost any certificate. An ecdsa csr generator produces a smaller, faster key for equivalent security, a 256-bit ECDSA key is roughly as strong as a 3072-bit RSA key, with faster handshakes and less bandwidth, worth choosing when you control both ends of the connection and know modern TLS support isn't a concern, otherwise RSA remains the more broadly compatible pick.
What Subject Alternative Names (SAN) Actually Do
A csr with san generator lets one certificate cover multiple hostnames, example.com and www.example.com and api.example.com, in a single request instead of issuing a separate certificate per domain. Modern browsers actually require SAN entries now, the CSR's Subject Common Name alone isn't enough for validation anymore, so any real-world certificate needs at least one SAN matching the domain being secured. Normally this means hand-writing an OpenSSL config file with a [ san ] section, this csr generator no openssl tool handles that entirely through a plain list of domain names instead.
Common Uses
Requesting a new certificate from a certificate authority like Let's Encrypt, DigiCert, or Sectigo, renewing an expiring certificate with a fresh key pair instead of reusing an old private key, and generating a multi-domain csr and private key generator output for a service that needs to cover several subdomains at once are the most common reasons to reach for this ssl csr generator, also usable as a general pkcs10 csr generator. It's also useful for internal or self-signed certificate setups where you control the whole chain and just need a properly formatted CSR to work from.