JSON to Properties Converter
Convert JSON to Java .properties format online. Nested objects and arrays are flattened into dot-notation keys — all in your browser.
Features
☕ Java-Compatible Output
- Dot-notation flattening for nested objects
- Numeric index segments for array items
- Proper escaping of backslashes and newlines
- Compatible with
java.util.Properties
⚡ Privacy-First
- All conversion happens in your browser
- No data ever sent to a server
- Pairs with our Properties to JSON converter
- Download or copy the resulting properties file instantly
🌱 Spring Boot Ready
- Same dot-notation Spring Boot's
@ConfigurationPropertiesexpects - Great for migrating a JSON config to
application.properties - Works with any JVM app that reads
.propertiesfiles - Standard Java
Propertiesload format
JSON to Properties Guide
Java's .properties format is one of the oldest configuration formats still in daily use — every JVM ships with java.util.Properties to read it, and frameworks like Spring Boot build their entire externalized-configuration system on top of it. Unlike JSON, a properties file has no native structure at all: it's a flat list of key=value pairs. The convention the whole Java ecosystem has settled on for representing nested config is dot-notation keys — database.host=localhost instead of a JSON object {"database": {"host": "localhost"}} — and that's exactly what this converter produces.
Arrays are flattened the same way, using the array index as a path segment: a JSON array {"tags": ["a", "b"]} becomes tags.0=a and tags.1=b. This exactly matches the convention Spring Boot's @ConfigurationProperties binding expects for list-typed fields, so a properties file generated here can usually be dropped straight into a Spring Boot application.properties file.
Frequently Asked Questions
Why dots instead of some other separator?
Dot-notation for nested properties predates Spring — it comes from Java's own naming conventions (package.Class.field) and was adopted directly by java.util.Properties-based configuration systems. It's now so standard that virtually every JVM framework's configuration binder expects it.
What happens to special characters in values?
Backslashes and newlines are escaped (\\ and \n) so the value round-trips correctly when read back by a standard .properties parser — an unescaped backslash or literal newline would otherwise break the file's line-based format.
Can I use this output directly in Spring Boot?
Yes — save the output as application.properties (or merge it into your existing one) and Spring's configuration binder will read the dot-notation keys the same way it reads any other properties file, including binding array-style keys to List fields.
Does it handle deeply nested JSON?
Yes — the flattening is fully recursive, so a JSON object nested five levels deep produces a key with five dot-separated segments, exactly mirroring the structure. There's no practical depth limit beyond what your JSON itself contains.