Regex Editor & Tester
Build, test, and debug regular expressions
Build, test, and debug regular expressions
Matches IETF locale tags consisting of a 2-3 lowercase letter language code followed by a hyphen and 2-3 uppercase letter country/region code. Examples include 'en-US', 'fr-FR', and 'zh-CN'. Useful for validating locale strings in internationalization (i18n) contexts, form validations, or parsing language preferences in web applications.