JSON to YAML Converter - Convert Bidirectionally Online
Convert between JSON and YAML formats instantly with real-time validation. Perfect for Kubernetes configs, Docker Compose, and CI/CD pipelines.
Frequently Asked Questions
What is a JSON-YAML converter?
A JSON-YAML converter is a tool that transforms data between JSON (JavaScript Object Notation) and YAML (YAML Ain't Markup Language) formats. JSON uses braces, brackets, and double quotes for structure, while YAML uses indentation and minimal punctuation for a more human-readable format. Both represent the same data structures (objects/mappings, arrays/sequences, and scalar values), making lossless bidirectional conversion possible. Developers frequently need to convert between these formats when working with APIs (which use JSON) and configuration files (which often use YAML).
How do I use this JSON-YAML converter?
1. Select your conversion direction using the tabs: JSON to YAML or YAML to JSON. 2. Paste your data into the input area (left panel on desktop, top panel on mobile). 3. The conversion happens automatically in real-time as you type (or click Convert if auto-convert is disabled). 4. Review the converted output in the output area. 5. Adjust formatting options (indentation, sort keys) as needed. 6. Click the Copy button to copy the result to your clipboard. 7. Optionally use Download to save the output as a file (.json or .yaml). 8. Use the Swap button to quickly reverse direction with your current data.
Is my data safe? Does it get sent to a server?
Your data is 100% safe and never leaves your browser. This converter uses the js-yaml library running entirely in client-side JavaScript. No data is transmitted to any server, stored in any database, or logged anywhere. All parsing, validation, and conversion happens locally on your device. You can verify this by disconnecting from the internet — the tool works fully offline after the initial page load. This makes it safe for converting sensitive configuration files, API keys, and credentials.
What happens to YAML comments during conversion?
YAML comments (lines starting with #) are lost when converting YAML to JSON because JSON does not support comments. This is a fundamental limitation of the JSON format, not a limitation of this tool. If you convert YAML to JSON and then back to YAML, the comments will not be preserved. For this reason, we recommend keeping a backup of your original YAML file if it contains important comments. The data values themselves are always preserved accurately during conversion.
What YAML features are supported?
This converter supports the YAML 1.2 specification including: mappings (objects), sequences (arrays), scalar values (strings, integers, floats, booleans, null), multi-line strings (literal | and folded > block scalars), nested structures of arbitrary depth, and quoted strings. Basic anchor (&) and alias (*) resolution is supported. However, some advanced YAML features like custom tags (!!) and complex merge keys may have limited support. The converter handles all data types that have a JSON equivalent.
Why might my YAML-to-JSON conversion fail?
Common reasons for YAML parsing errors include: incorrect indentation (YAML is whitespace-sensitive and requires consistent spacing), mixing tabs and spaces (YAML should use spaces only), unquoted special characters in strings (colons, brackets, or braces that YAML interprets as structure), duplicate keys in a mapping, and invalid multi-line string indicators. The error message will show the exact line and column where the issue was detected to help you fix the problem.
What is the difference between JSON and YAML?
JSON and YAML both represent structured data but differ in syntax and use cases. JSON uses braces {} for objects, brackets [] for arrays, requires double-quoted keys, and does not support comments. YAML uses indentation for structure, does not require quotes for most strings, supports comments with #, and has additional features like multi-line strings and anchors. JSON is more common in APIs, web services, and programmatic data exchange. YAML is more common in configuration files (Kubernetes, Docker Compose, CI/CD pipelines) where human readability is prioritized.
Code Examples
// JSON to YAML conversion using js-yaml library
// Install: npm install js-yaml
const yaml = require('js-yaml');
function jsonToYaml(jsonString, options = {}) {
const { indent = 2, sortKeys = false } = options;
try {
const parsed = JSON.parse(jsonString);
return yaml.dump(parsed, { indent, sortKeys, lineWidth: -1 });
} catch (error) {
return `Error: ${error.message}`;
}
}
function yamlToJson(yamlString, options = {}) {
const { indent = 2, sortKeys = false } = options;
try {
const parsed = yaml.load(yamlString);
return JSON.stringify(parsed, null, indent);
} catch (error) {
return `Error: ${error.message}`;
}
}
// Example
const json = '{"name": "app", "version": "1.0", "debug": true}';
console.log(jsonToYaml(json));
// name: app
// version: '1.0'
// debug: true