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Convert Java .properties files to JSON

Java .properties files use key=value pairs with dot-notation for nesting. Convert to JSON for use in JavaScript environments and structured access.

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    Java .properties files use KEY=VALUE or KEY:VALUE pairs, with dot-notation for hierarchical keys (e.g., app.database.host=localhost). Comments start with # or !. They are common in Java applications for configuration and internationalization (i18n) messages.

  2. 2
    TOML Converter →

    Parse the .properties file and convert to JSON. Dot-notation keys are expanded into nested objects: app.database.host becomes {app: {database: {host: ...}}}. This makes the structure explicit and navigable.

  3. 3
    JSON Formatter →

    Format the converted JSON. Verify that dot-notation keys were correctly nested. Properties files often use inconsistent key naming — formatting normalizes the output and makes structural issues visible.

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    For i18n message bundles, the conversion produces a JSON object that JavaScript i18n libraries (i18next, FormatJS) can consume directly. Map Java message format ({0}, {1}) to ICU MessageFormat ({name}, {count, plural, ...}) during conversion if needed.

Frequently asked questions

How are special characters handled in .properties?
Backslash escapes: \n (newline), \t (tab), \= (literal =), \: (literal :), \\ (literal backslash). Unicode: \uXXXX. The conversion tool should handle these escapes and produce the correct characters in JSON.
Can I convert JSON back to .properties?
Yes, but only for flat or shallowly nested JSON. Deep nesting and arrays do not map cleanly to .properties dot-notation. If you need round-trip conversion, keep the JSON flat or use a format that supports nesting natively (YAML, TOML).

Workflows that solve this

Compare two YAML configs via JSON
Convert YAML configs to JSON for diff-friendly comparison of structured values.
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Encode a JSON payload for URL transport
Prepare a JSON document for a URL parameter: pretty-print, Base64-encode, then percent-encode — the exact inverse of the nested-parameter decode chain.
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HJSON to JSON Format
Format HJSON then convert to standard JSON.
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Format JSON and compute integrity checksum
Pretty-print a JSON document and compute a CRC32 checksum to detect any subsequent modifications.
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Minify and validate JSON
Format JSON for inspection and validate it is syntactically correct in one pass.
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Format JSON and generate TypeScript interface
Format a JSON document then infer a TypeScript interface definition in one chain.
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Validate, format, then convert JSON to YAML
Convert a (possibly minified) JSON config to YAML, catching syntax errors at the first node instead of producing subtly wrong YAML.
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JSON5 to JSON Format
Format JSON5 then convert to standard JSON.
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JSONC to JSON Format
Format JSONC (JSON with comments) then convert to standard JSON.
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Decode and format a JWT payload
Parse a JWT token, extract its payload, and format the JSON for inspection.
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Parse Query String and Format JSON
Parse query string into key-value pairs then format as JSON.
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Convert TOML to JSON
Parse a TOML configuration file into JSON for tools and APIs that expect JSON input.
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TOML to JSON to CSV
Convert TOML to JSON then to CSV for data export.
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Convert TOML to JSON then YAML
Transform a TOML config into YAML via JSON for Kubernetes or CI tooling.
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Convert TOML to YAML via JSON
Transform a TOML configuration file into YAML format, using JSON as an intermediate representation.
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Decode nested URL parameter (Base64 JSON)
Unwrap a URL parameter that carries URL-encoded Base64 JSON into readable, formatted JSON.
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Generate TypeScript interfaces from YAML
Convert a YAML document to TypeScript interface definitions, using JSON as an intermediate format.
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Learn more

Want to understand why?

How to Convert YAML to TOML
Convert YAML configuration files to TOML format for use in Rust, Python, and other TOML-native tools.
TUTORIAL
How to Use TOML Arrays
A beginner-level guide covering toml, arrays, config. Includes step-by-step instructions, common errors, troubleshooting tips, and security considerations for toml.
TUTORIAL
INI Keys
INI keys define configuration entries as key=value pairs; values are always strings and belong to the current section.
GLOSSARY
INI Sections
INI sections use [section] headers to group key-value pairs; they are the organizational unit of an INI file.
GLOSSARY

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