π YAML to Properties
π Input YAML
What Can the YAML to Properties Converter Do?
The YAML to Properties converter is a free online tool for developers that transforms YAML configuration files into Java Properties format. It automatically flattens nested keys into dot-separated paths, expands arrays with numeric indices, and handles type conversion. Ideal for Spring Boot application.yml to application.properties migration.
Core Features
- Nested Key Flattening: Automatically expands nested objects to dot-separated keys (server.port=8080)
- Array Index Expansion: Lists become indexed keys (servers.0.name=prod)
- Configurable Separator: Choose dot, underscore, or hyphen as key separator
- Unicode Escaping: Optional non-ASCII character escaping for Java compatibility
- Key Sorting: Sort output alphabetically for consistent diffs
- Drag & Drop Import: Drag YAML files directly into the input area
How to Use
1. Paste YAML content in the input area, or drag a .yml file
2. Choose key separator style (dot for Spring, underscore for env vars)
3. Toggle sorting and Unicode escaping as needed
4. Click "Convert" or use Ctrl+Enter shortcut
5. Copy the result or download as .properties file
Use Cases
Case 1: Spring Boot Migration
Convert application.yml to application.properties when migrating Spring Boot projects from YAML to Properties configuration format.
Case 2: Environment Variable Generation
Generate underscore-separated environment variable names from YAML config for Docker/Kubernetes deployment configurations.
Case 3: Legacy System Integration
Convert modern YAML configs to Properties format for integration with legacy Java systems that only read .properties files.
Case 4: Config Comparison
Flatten YAML to Properties for easier side-by-side comparison of configuration differences between environments.
Extended Knowledge
Java Properties files use a flat key=value format where nested structures must be represented with dot-separated keys. Spring Boot introduced YAML support but Properties remains the default. YAML offers better readability with nesting and lists, while Properties is simpler and more universally supported. The conversion preserves semantic equivalence: YAML lists become indexed keys (list.0, list.1), and nested objects become dotted paths. Properties files use ISO-8859-1 encoding by default, so non-ASCII characters should be Unicode-escaped for maximum compatibility.
β What YAML features does the converter support?
It supports nested object flattening to dot-separated keys, array index expansion, string/number/boolean type auto-detection, and comment handling.
β How are nested YAML keys converted?
Nested keys are automatically flattened to dot-separated format, e.g. server.port=8080. Arrays use indices like servers.0.name=prod.
β Is my data uploaded to a server?
No. All conversion logic runs locally in your browser. Your configuration data never leaves your device.
β Does it support Spring Boot config conversion?
Yes. Converting application.yml to application.properties is the most common use case. Key flattening rules match Spring Boot conventions.
β Can non-ASCII characters be converted correctly?
Yes. Unicode characters are fully supported. Non-ASCII values are preserved or optionally escaped to Unicode escape sequences.
β How are special characters handled in Properties?
Special characters (=, :, spaces) are automatically backslash-escaped to ensure the output Properties file is syntactically correct.
β Can I convert multiple YAML files at once?
Yes. You can drag and drop multiple YAML files and the tool will convert and merge them sequentially.