Accept-Language
RequestActiveThe Accept-Language header tells the server which natural languages the client prefers, in priority order. The server uses this for content negotiation to return localized content. Quality values (q=) weight preferences from 0.0 to 1.0. Most web apps prefer explicit URL-based locale selection over relying on Accept-Language.
Accept-Language: <language>[;q=<weight>], *
Description
Accept-Language enables language-based content negotiation. Each language tag follows BCP 47 (e.g., en-US, fr, zh-Hant). Quality values specify preference order. The server selects the best matching language from its available translations. For SEO, explicit URLs (/en/, /fr/) are preferred over header-based negotiation.
Directives
| Directive | Description |
|---|---|
| <language> | BCP 47 language tag: en, en-US, fr-CA, zh-Hant, etc. |
| q=<weight> | Quality value 0.0–1.0. Default 1.0 (highest priority). |
| * | Wildcard – matches any language not already listed. |
Examples
US English preferred
http
Accept-Language: en-US,en;q=0.9,fr;q=0.8Any language
http
Accept-Language: *