List of valid ISO codes

ISO 639-1 codes


The ISO 639-1 codes are standardized two-letter codes used to represent languages. They are part of the ISO 639 standard maintained by the International Organization for Standardization.


In short:
ISO 639-1 codes are two-letter abbreviations (like en for English or fr for French) used to identify languages in software, websites, and international systems.


They're commonly used in:

  • Web content (lang="en")
  • Locale settings (en_US, fr_CA) - combined with ISO 3166
  • Translation files
  • APIs and databases

List of valid codes:

ISO 3166 codes


ISO 3166 is a globally recognized standard that assigns unique short codes to countries and territories (e.g., US for the United States, FR for France).

These standardized country codes are essential in SEO, international targeting, and geolocation, especially when configuring hreflang tags combined with ISO 639-1 (hreflang="en-US" for English localized in USA).

By using ISO 3166 codes correctly, websites can:

  • Improve multilingual SEO through accurate language and country targeting.
  • Enhance user experience by serving content tailored to the visitor's location.
  • Support structured data, international redirects, and analytics tracking.

List of valid codes: