Convert JSON to Java Properties online
Upload a JSON file and download it as Java .properties. Translation keys, plurals and placeholders are preserved. Free, no account needed.
Pick the source format or let the converter detect it from the file.
Used when the source format holds one language per file. Also used as the source language for XLIFF output.
Choose the format you want to download.
Key=value resource bundles used by Java, Spring Boot and Kotlin backends. Each language lives in its own messages_xx.properties file next to the default bundle.
Need it the other way round? Convert Java Properties to JSON.
From: JSON
A flat or nested key-value JSON file with translations for one language. It is the most common format for web and mobile apps because every language can parse it and it maps directly to the way i18n libraries look up strings.
Used by: i18next, react-intl, vue-i18n, next-intl, Angular, Node.js. One language per file. Read the JSON format guide.
{
"hello.world": "Hello World!",
"my_address": "Address",
"nested": {
"translation": {
"key": "nested translation key"
}
}
}To: Java .properties
Key=value resource bundles used by Java, Spring Boot and Kotlin backends. Each language lives in its own messages_xx.properties file next to the default bundle.
Used by: Java, Spring Boot, Kotlin, Thymeleaf. One language per file. Read the Java Properties format guide.
# example comment
user.hello=Hello, {0}
hello.world=Hello World!How to convert JSON to Java Properties
- Drop your .json file into the converter above, or paste its content.
- Confirm the language of the file. It is guessed from the file name, for example
de.jsonormessages_pt-BR.properties. - Click Convert. You get one .properties file per language.
- Preview the result, copy it or download the files.
What changes between JSON and Java Properties
- Keys, texts, plural forms and placeholders are mapped one to one. Comments and descriptions are kept when both formats support them.
Convert and translate in one place
If you need the Java Properties file in more languages, the fastest route is a free SimpleLocalize project: import the JSON file, add languages, run auto-translation with DeepL, Google Translate, OpenAI, Claude or Gemini, and download the result as Java Properties. The CLI does the same from CI with upload and download commands, so the conversion becomes part of your build. See also translating JSON files.
Frequently asked questions
Is the converter free?
Yes. There is no signup and no limit on the number of conversions beyond a few requests per second.
Are my files stored?
No. The file is parsed in memory, converted and returned in the same request. Nothing is written to disk or a database.
What about plurals and placeholders?
Plural forms are normalized to ICU message syntax and written back in the native form of Java Properties. Placeholders are kept, and Apple and Android specific syntax is translated between platforms. Read more in the pluralization guide.
Convert JSON to other formats
Translate your Java Properties files
- Import JSON or Java Properties files into a free project
- Auto-translate with DeepL, Google, OpenAI, Claude or Gemini
- Download in any of the supported formats or publish to the CDN