The first step is always Transport Layer Security. Without proper Rest API TLS configuration, every packet crossing the wire is an open secret.
TLS is more than HTTPS. It’s a handshake between client and server that guards integrity, confidentiality, and authenticity. Configuring it wrong means false security—an unlocked door painted shut.
Start with a valid, trusted certificate. Use a reputable Certificate Authority and set strong cipher suites. Disable outdated protocols like SSLv3 and TLS 1.0. Enforce TLS 1.2 or TLS 1.3 for modern encryption and forward secrecy. Configure your server to reject weak ciphers, even if a client requests them.
On the API side, require HTTPS for all endpoints. Redirect plain HTTP to HTTPS and implement HSTS headers to lock clients into encrypted sessions. For REST clients, validate certificates properly—never skip signature checks or host name verification. Pin server certificates or public keys to protect against compromised CAs.