HTTP redirect (301 vs 302)

When a browser asks for a URL and the server answers with a redirect status code, it forwards the browser to a new address. A 301 says "this moved permanently," and browsers and search engines cache it hard. A 302 says "go here for now," and is not cached the same way, so the destination stays changeable.

That difference is why a dynamic QR code uses a 302: the whole point is to repoint the link later, so you never want a browser pinning the old destination. TangoQR's redirect spine answers scans with a 302 for exactly this reason. See the full redirect status code reference.