If you use i18n features like Intl in your Node.js application, you need ICU (International Components for Unicode). Your local node installation will most likely have the full ICU installed, but it’s often missing on servers or containers.

Node will fall back to the locale it has installed, so consider writing a test to make sure your locale is available. Below are two options on how to get full ICU data.

Compile node yourself

Use the flag --with-intl=full-icu to compile node with full ICU (see ICU options ).

Provide ICU data at runtime

Install the package full-icu and tell node to use it by either setting the environment variable NODE_ICU_DATA=node_modules/full-icu or passing --icu-data-dir=node_modules/full-icu. You can find more detailed information in the official documentation .