Translate FormatJS and React Intl catalogs with Hyperlocalise

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Source file

{
    "home.greeting": {
        "defaultMessage": "Hello, {name}!",
        "description": "Greeting on the home screen"
    }
}

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Configure your files

locales:
    source: en-US
    targets:
        - es-ES

buckets:
    messages:
        files:
            - from: locales/en-US/messages.json
              to: locales/{{target}}/messages.json

llm:
    profiles:
        default:
            provider: openai
            model: gpt-5.2

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Translate

hyperlocalise run --dry-run
hyperlocalise run

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Behavior and limitations

• Every top-level entry must be a message object with a string defaultMessage for strict catalog detection.
• description supplies translation context. Writeback updates defaultMessage while retaining catalog metadata.
• Preserve ICU arguments and plural/select syntax in messages. Review generated translations with check.
• Use extract to create a catalog from React Intl source. Static JS/TS catalogs are supported too.

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Next steps

• Check translations before committing generated files.
• Local translation workflow explains repeat runs.
• Browse all file formats.

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Related guides

• Translate React Intl messages end to end.
• Fix ICU and placeholder errors.

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Related formats

• JSON localization
• JavaScript and TypeScript locale
• Translate a React Intl app