YAML ↔ JSON Converter

Convert YAML to JSON or JSON to YAML instantly. Auto-detects input format. Supports YAML anchors & aliases, syntax validation, copy-to-clipboard, and file download. Free, browser-based, no data uploaded.

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YAML ↔ JSON Converter

Convert between YAML and JSON with automatic format detection. Paste your input, click Convert, and get the result instantly — no server involved.

Features

Common use cases

YAML vs JSON: Key Differences

FeatureYAMLJSON
SyntaxIndentation-basedBrace and bracket delimited
CommentsSupported (# comment)Not supported
StringsQuotes optionalQuotes required
MultilineNative block scalarsEscaped \n only
AnchorsSupported (&anchor, *alias)Not supported

YAML is human-friendly for configuration files (Docker Compose, Kubernetes, GitHub Actions). JSON is the standard for API responses and data interchange.

How the Converter Works

The converter uses a YAML parser that supports the full YAML 1.2 specification, including anchors and merge keys (<<). When converting to JSON, anchor references are fully expanded — the output is always flat, valid JSON with no YAML-specific constructs.

For JSON-to-YAML conversion, the tool generates clean block-style YAML: objects are expanded to indented key-value pairs, arrays use the - item list syntax, and long strings are kept as literals when possible.

Privacy

All conversion happens locally in your browser. Your YAML and JSON data is never sent to a server.

FAQ

What is the difference between YAML and JSON?

YAML (YAML Ain't Markup Language) is a human-friendly data serialization format often used for configuration files. JSON (JavaScript Object Notation) is the standard data interchange format for web APIs. YAML supports comments, multi-line strings, and anchors; JSON is stricter and more portable. This tool converts between both formats instantly.

Does the tool auto-detect the input format?

Yes. The converter automatically detects whether your input is JSON (starts with { or [) or YAML, and converts in the correct direction. You can also choose the direction manually using the dropdown.

What are YAML anchors and aliases?

YAML anchors (&name) define reusable blocks and aliases (*name) reference them. The merge key (<<) allows merging anchor content into another map. This tool fully supports anchors and aliases — they are resolved and inlined in the JSON output.

Is my data sent to a server?

No. All conversion runs locally in your browser using js-yaml, a pure JavaScript library. Your data never leaves your device and is not stored, logged, or shared.

What happens if I paste invalid YAML or JSON?

The tool validates your input and shows a clear error message with the position of the problem. No output is generated until the input is valid.