HTTP Public Key Pinning, or HPKP, is a security policy delivered via a HTTP response header much like HSTS and CSP. It allows a host to provide information to a user agent about which cryptographic identities it should accept from the host in the future. This can protect a host website from a security compromise at a Certificate Authority where rogue certificates may be issued for your hostname.
HTTPie (pronounced aitch-tee-tee-pie) is a command line HTTP client. Its goal is to make CLI interaction with web services as human-friendly as possible. It provides a simple http command that allows for sending arbitrary HTTP requests using a simple and natural syntax, and displays colorized output. HTTPie can be used for testing, debugging, and generally interacting with HTTP servers.