Localization is the process of adapting content for different locales. When you localize an entry, it no longer inherits values from its fallback language and becomes an independent version.
Unlocalized entries inherit content from their fallback locale. To make changes specific to a locale, you must first localize the entry. This is done by saving the entry in the target locale.
Once localized, the entry becomes independent and can have its own content, version history, and publishing status.
When an entry is localized:
As shown in the diagram below, localizing an entry breaks the inheritance chain between master, fallback, and child entries, resulting in a standalone localized version.

Once an entry has been localized, you can also unlocalize it at any time to restore inheritance from the fallback locale.
Localization determines how content is returned in Delivery API responses across locales and environments. This is particularly important when building frontend applications or debugging content issues.
Note: Fallback behavior works only if a fallback locale is configured in your stack.
Because localization creates independent versions of entries, content and publish status can vary across locales.
Before troubleshooting missing or incorrect localized content, ensure that:
Use this request to retrieve content for a specific locale:
curl -sS "https://<cdn-host>/v3/content_types/<content_type_uid>/entries/<entry_uid>?environment=<environment>&locale=fr-fr" \
-H "api_key: <stack_api_key>" \
-H "access_token: <delivery_token>"Use this when the localized version may not be published:
curl -sS "https://<cdn-host>/v3/content_types/<content_type_uid>/entries/<entry_uid>?environment=<environment>&locale=fr-fr&include_fallback=true" \
-H "api_key: <stack_api_key>" \
-H "access_token: <delivery_token>"Use this to debug publish status across locales and environments:
curl -sS "https://<cdn-host>/v3/content_types/<content_type_uid>/entries/<entry_uid>?environment=<environment>&locale=fr-fr&include_publish_details=true" \
-H "api_key: <stack_api_key>" \
-H "access_token: <delivery_token>"| Symptom | Likely Cause | What to Check |
|---|---|---|
| Locale returns empty or missing fields | Localized entry is not published | Verify publish status for the locale and environment |
| Incorrect language is returned | Locale not specified in request | Ensure locale=<target-locale> is included |
| Fallback not working as expected | Fallback configuration mismatch | Confirm fallback locale setup and use include_fallback=true |
| Works in one environment but not another | Environment mismatch | Verify the environment parameter and token scope |
Note: