Convert Java Properties to Multi-language JSON online
Upload a Java .properties file and download it as Multi-language JSON. 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.
A single JSON file where every translation key holds an object with one entry per language. Handy for small projects, static sites and CDN delivery because all languages travel together.
Need it the other way round? Convert Multi-language JSON to Java Properties.
From: 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!To: Multi-language JSON
A single JSON file where every translation key holds an object with one entry per language. Handy for small projects, static sites and CDN delivery because all languages travel together.
Used by: custom i18n setups, static site generators, CDN delivery. All languages in one file. Read the Multi-language JSON format guide.
{
"en_US": {
"hello.world": "Hello World!",
"my_address": "My address"
},
"pl_PL": {
"hello.world": "Witaj Świecie!",
"my_address": "Mój adres"
}
}How to convert Java Properties to Multi-language JSON
- Drop your .properties 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 a single .json file with all languages.
- Preview the result, copy it or download the file.
What changes between Java Properties and Multi-language JSON
- Multi-language JSON keeps all languages together. A single Java Properties file produces a Multi-language JSON file with one language column; upload more files to a SimpleLocalize project to merge languages.
Convert and translate in one place
If you need the Multi-language JSON file in more languages, the fastest route is a free SimpleLocalize project: import the Java Properties file, add languages, run auto-translation with DeepL, Google Translate, OpenAI, Claude or Gemini, and download the result as Multi-language JSON. The CLI does the same from CI with upload and download commands, so the conversion becomes part of your build. See also translating Java Properties 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 Multi-language JSON. Placeholders are kept, and Apple and Android specific syntax is translated between platforms. Read more in the pluralization guide.
Convert Java Properties to other formats
Translate your Multi-language JSON files
- Import Java Properties or Multi-language JSON 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