What it does
The Language Dictionary API gives you the full list of ISO 639-1 languages as JSON. One request returns every language with its two-letter code, its English name and its native name, so you can build language pickers and translate language codes into readable names without maintaining your own list.
It is a single GET request with no parameters. The response is a data array with one object per language: key holds the ISO 639-1 code, value the name in English and native the name in the language itself. For German that is de, German and Deutsch.
The native name is what makes a language picker work for everyone. A Greek speaker looks for Ελληνικά, not Greek, and a Japanese speaker for 日本語. Showing both names lets users find their language whatever language your interface is in. Common uses include language selectors in apps, sign-up forms and user profiles, showing a readable name for language codes stored in your database, validating language codes sent to your API, and labelling content, subtitles and translations by language. Because it is a small reference list, you can fetch it once and cache it in your app.
To find out which language a piece of text is written in, use the Language Detection API, which returns the same ISO 639-1 codes. To see every likely language with a probability, use the Detect Text Language Probabilities API. For country names and codes to go with your language list, use the Countries Dictionary API, and for currencies, the Currencies Dictionary API.
You can try it right here in the playground. Start for free with 5 API calls a day, no card required, and see the full list before you commit.
The API is also available through ApyHub MCP, so AI agents can look up language codes and names directly instead of relying on memory.
