An Introduction to HTTP

HTTP — the HyperText Transfer Protocol — is the language browsers and servers use to exchange data on the web. When you type a URL into your browser, DNS translates that human-readable name into a numeric IP address that identifies the actual server machine, and then your browser opens a connection to it. Every exchange follows the same pattern: your browser sends a request, the server sends back a response. Requests carry a verb that describes the intended action: GET retrieves data without changing anything, POST creates a new resource, PUT replaces an existing one entirely, PATCH updates only specific fields, and DELETE removes it. Requests also carry headers — key-value metadata like the content type you accept or the credentials you hold — and optionally a body with the payload you are sending. Responses come back with a three-digit status code: the 200s mean success, the 300s are redirects, the 400s mean the client made an error, and the 500s mean something went wrong on the server. Every interaction on the web — loading a page, submitting a form, calling an API — reduces to this loop: one request, one response.