Banner or redirect?

Show a banner	Redirect
Visitor experience	Sees the page, then a polite offer	Lands directly on their language
Visitor stays in control	Yes	Less; they can still switch back with the switcher
Works with page caching and CDN caching	Yes, always	Country: only on pages not served from cache. Browser: yes
Search engines	Never shown	Never redirected
Good for	Most sites	Sites with clear language markets and no full-page cache

Why country redirects need uncached pages. A country redirect is decided on your server before the page is sent. If a page cache (WP Rocket, LiteSpeed Cache, Cloudflare APO, your host’s cache…) serves a saved copy, your server never sees the request. Redirect responses themselves are sent with no-cache headers so a cache never stores them.

Browser redirects also work on cached pages, because the browser can redirect itself after the page loads.

The banner always works on cached pages: after the page loads, it asks your server for the visitor’s suggestion, and that request is never cached.