How it works
The JSON to Properties converter transforms a JSON object into a Java .properties file format — mapping JSON properties to key=value lines. Use it when migrating JSON configuration back to Java applications, generating internationalization resource bundles from JSON translation files, or producing .properties config for legacy systems that require this format.
Translation management systems and modern i18n tools (Phrase, Lokalise, Crowdin) use JSON as the working format for translations. Java internationalization ResourceBundle requires .properties files. This tool converts the JSON output from translation tools to the .properties format required by the Java runtime.
How to use it: paste a JSON object or upload a .json file. The tool traverses the JSON and produces key=value lines. For nested objects, keys are flattened using dot notation ({"server":{"port":8080}} → server.port=8080). Click Copy Output or Download .properties.
Array handling: JSON arrays can be flattened as indexed keys (items.0=a, items.1=b, items.2=c) or joined as comma-separated values (items=a,b,c) — toggle the option based on your target application's expectation.
Special characters: values containing special characters (=, :, #, !) are escaped appropriately. Non-ASCII characters are either preserved as UTF-8 or encoded as Unicode escapes (\uXXXX) depending on your target Java version.
Privacy: JSON-to-properties conversion runs in the browser.
Frequently Asked Questions
- Each level of nesting adds a dot-separated segment to the key: {"server":{"port":8080}} → server.port=8080. Arrays use numeric indices: {"items":["a","b"]} → items.0=a, items.1=b. This matches Spring Boot's externalized configuration key binding convention.
- Characters that have special meaning in .properties syntax (=, :, #, !, \, and leading whitespace) are escaped with a backslash in the output value. This produces a .properties file that parses correctly even if values contain these characters.
- JSON null values are output as empty values in the .properties file: key= (key with no value). Some Java property readers treat an empty string as null; others treat it as an empty string. Verify your application's null-handling behavior.
- Modern Java (Java 9+) property files use UTF-8 encoding directly — non-ASCII characters can appear as-is in the file. Legacy Java code (Java 8 and earlier) uses Latin-1 encoding and requires \uXXXX escapes for non-ASCII. Toggle 'Java 8 compatibility' to encode non-ASCII as \uXXXX sequences.