Hash-Based vs Path-Based Routing

SPAs need URLs that the browser does not fetch. Two approaches: hash-based uses the fragment (everything after #) which the browser never sends to the server, and path-based uses the pathname plus History API trickery.

URLs look like https://example.com/#/about. The server only sees / and serves the same HTML for every URL. Client JS reads location.hash to decide which view to render. Simple, requires no server config.