2.1. HTTP About
Request vs. Response
URI vs. URL vs. URN
HTTP vs. HTTPS
HTTP/1.1 vs. HTTP/2.0 vs. HTTP/3
Methods
Statuses
Headers
Let's Encrypt - Free SSL/TLS certificates
https://certbot.eff.org/instructions?ws=nginx&os=ubuntufocal
HTTPbin.org https://httpbin.org/
Petstore OpenAPI https://petstore3.swagger.io/