whoami.filippo.io powers a diagnostic service that reports what your client and connection look like from the other side, making it a handy mirror for network and TLS debugging. It surfaces details such as your IP address, protocol versions, cipher suites, SNI, and other attributes that are otherwise tedious to confirm across layers. The tool emphasizes clarity and minimalism, helping engineers quickly verify configuration changes in browsers, proxies, VPNs, or CLI tools. It is especially helpful when validating modern TLS features like ALPN, HTTP versions, and certificate behavior under different client stacks. Because the output is human-friendly, it doubles as an educational resource for understanding how transport and application-layer negotiations actually manifest. Teams use it to troubleshoot misconfigurations and confirm policy enforcement without setting up their own inspection endpoints.