0.9,fr-fr Apr 2026

When a server receives this header, it attempts to match the request with available content:

: The "q" (quality value) is a weight from 0.0 to 1.0. A value of 0.9 indicates a high priority, though typically slightly lower than the primary language (which defaults to 1.0 if not specified). How Servers Use It

A full header might look like this: Accept-Language: en-US,en;q=0.9,fr-FR;q=0.8 This tells the server: "I prefer US English (1.0), but I'll take any English (0.9) or French from France (0.8) if that's what you have". 0.9,fr-FR

Are you trying to or set up language detection for a specific web application? The role of Accept-Language header in software localization

: If fr-FR is not available, it may look for a general French version ( fr ) or the next language in the user's priority list. When a server receives this header, it attempts

The string "0.9,fr-FR" is typically a segment of an , which tells a web server which languages a user prefers for the content they receive. Understanding the Syntax

: If the server has a French (France) version of the page, it will serve that. Are you trying to or set up language

: Developers use these strings in languages like Python (Flask) or Node.js to automatically redirect users to the correct localized version of a site. Common Example