How each country writes dates, numbers and units.

Date and time patterns, number separators, first day of the week and measurement system, per country and language.

GET/api/v1/locales/de-DE200

{
  "locale": "de-DE",
  "date_format": "dd.MM.y",
  "decimal": ",",
  "group": ".",
  "first_day": "monday",
  "measurement": "metric"
}

Simplified example, not live data.

What locale data gives you

Dates and times: Short and long patterns, 12 or 24 hour clocks and the first day of the week.
Numbers and money: Decimal and grouping separators and where the currency symbol goes.
Measurement: Metric, US or UK customary units, per country.
Built on shared standards: Derived from CLDR and attributed to it on every record.

Source, licence and verification status travel with the data. This is an excerpt of the register behind the API.

Source	Used for	Licence
Unicode CLDR	Locale attributes	Unicode License

Create a key in your account and send it in the x-api-key header.

curl "https://locale.atlasref.dev/api/v1/locales/de-DE" \
  -H "x-api-key: $ATLASREF_KEY"

The other datasets use the same identifiers and the same rules about sources.