SSL tools Certificate/key matcher
Check that a certificate and its private key (or CSR) really belong together — before installation, not after.
A certificate only works with the private key its CSR was created with. If you install the wrong key on the server (e.g. from an older CSR), the site stops working over HTTPS. This tool compares the public key embedded in the certificate against the CSR or private key you enter, and tells you whether they match — no command line needed.
Need a CSR? Create one in the CSR generator. Certificate in the wrong format? Convert it with the SSL converter.