Generate certificate signing requests and private keys without OpenSSL.
CSR.plus API is a free Security API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Ephemeral zero-knowledge encrypted data sharing
Screen crypto addresses, emails, websites, IDs and countries against OFAC, EU, UK sanctions lists
DNS, WHOIS/RDAP, SSL, subdomain enumeration, and email security in one parallel call
Yes. The CSR.plus API is listed in the Security category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The CSR.plus API requires no authentication, so you can start making requests without signing up.
Yes. The CSR.plus API supports CORS, so front-end JavaScript can call it directly.
Yes. The CSR.plus API is served over HTTPS, so it's safe to use in production.