TLS / Certificates
SSL certificates, TLS configuration and error diagnostics.
The tools in the TLS / Certificates category help you quickly check when an HTTPS site's SSL certificate expires, whether the intermediate chain is complete, and whether every domain you serve is listed in the certificate's SAN (Subject Alternative Names). They also cover checking which TLS versions a server supports (1.2/1.3), reviewing CAA records that restrict which certificate authorities may issue for your domain, decoding browser certificate errors such as NET::ERR_CERT_DATE_INVALID or SEC_ERROR_UNKNOWN_ISSUER, and decoding CSRs (Certificate Signing Requests). They're useful for site owners, backend and infrastructure engineers, and anyone searching for how to check SSL certificate expiry or diagnose an SSL error.
A typical workflow starts with expiry and chain. Confirm the certificate isn't about to expire, verify the trust chain is complete up to a trusted root, and make sure the hostname you connect to appears in the SAN. From there, tighten security by checking the negotiated TLS version and your CAA records. If a browser shows an error, paste the exact error code into a decoder to narrow the cause (expired, name mismatch, missing intermediate, or self-signed), then fix that specific issue. Before requesting a new certificate, use a CSR decoder to confirm the domain and organization details are correct so you don't issue the wrong cert.