Accept-Language Header

What is the Accept-Language header?

The Accept-Language request header tells the server which natural languages the client prefers, using language tags with optional quality (q) values to express relative preference. The server uses it during content negotiation to choose a language variant.

API Usage & Best Practices

• Use q-values to rank: A weight from 0 to 1 orders preferences, for example fr-CH, fr;q=0.9, en;q=0.8.
• Handle unsupported languages: If no acceptable language can be served, the server may respond with 406 Not Acceptable, though returning a sensible default is often friendlier.
• Confirm with Content-Language: The chosen variant should be echoed back in the response’s Content-Language header.

Examples

GET /articles/42 HTTP/1.1
Host: api.example.com
Accept-Language: fr-CH, fr;q=0.9, en;q=0.8, *;q=0.5