JSON to YAML Converter

The JSON to YAML Converter is a free, browser-based tool that transforms data between JSON and YAML in either direction. Paste JSON to get clean, human-readable YAML, or paste YAML to get valid, minifiable JSON - the converter auto-detects which format you pasted, validates it, and shows a clear error with the line number if something is wrong.

Everything runs client-side using the standard JSON.parse/JSON.stringify methods for JSON and the widely trusted js-yaml library for YAML, so your data never leaves your device and there is no upload, sign-up, or size limit beyond your browser's memory.

How to convert JSON to YAML (or YAML to JSON)

1. Paste your JSON or YAML into the input pane on the left.
2. Leave the direction on Auto-detect, or pick JSON → YAML or YAML → JSON explicitly.
3. Choose 2-space or 4-space indentation for the output.
4. Click Convert (or press Ctrl+Enter).
5. Read the result in the output pane, then use Copy or Download to save it.

What is the difference between JSON and YAML?

JSON (JavaScript Object Notation) is a compact, strict format built from braces, brackets, quotes, and commas - ideal for APIs and machine-to-machine exchange. YAML (YAML Ain't Markup Language) is a superset of JSON that uses indentation instead of braces, supports comments, and reads more like plain text, which is why it dominates configuration files for Docker, Kubernetes, GitHub Actions, and Ansible.

Because YAML is a superset of JSON, any valid JSON is already valid YAML, but the reverse is not true: YAML features such as comments, anchors, and multi-line strings have no direct JSON equivalent and are flattened or dropped when you convert back.

Why use this converter

• Bidirectional: one tool handles both JSON → YAML and YAML → JSON.
• Auto-detect: paste either format and the tool figures out the direction.
• Real validation: malformed input is caught and reported with a line number instead of a silent failure.
• Readable output: pick your indentation so the result fits your project's style.
• Private: 100% client-side, nothing is sent to a server.
• Portable: copy to clipboard or download a .yaml or .json file.

When to convert between JSON and YAML

Convert JSON to YAML when you are turning an API payload or a compact config into something a human will edit by hand, such as a Kubernetes manifest or a CI pipeline. Convert YAML to JSON when a program, API, or database needs strict structured data - for example feeding a config value into JavaScript. If you only need to tidy or shrink JSON rather than change formats, a dedicated JSON Formatter for pretty-printing or a JSON Minifier for stripping whitespace is the faster choice, and for validating readable config a YAML Formatter & Validator pairs well with this converter.

Tips for clean conversions

Keep keys consistent and avoid tabs in YAML - the spec requires spaces, and mixing them is the most common cause of parse errors. When converting deeply nested JSON, YAML's indentation makes the hierarchy far easier to scan, while converting back to JSON is the right move whenever you need to transform the data further into another structure such as XML with a JSON to XML Converter or import tabular data using a CSV to JSON Converter.

Frequently Asked Questions

Is my data uploaded to a server?

No. The entire conversion happens in your browser using client-side JavaScript. Your JSON and YAML never leave your device, which makes the tool safe for sensitive configuration and credentials.

Does the auto-detect always pick the right direction?

Auto-detect treats input that starts with a brace or bracket, or that parses as strict JSON, as JSON and converts it to YAML; otherwise it treats the input as YAML. If a rare edge case is guessed wrong, just switch the direction dropdown to JSON to YAML or YAML to JSON manually.

What happens to YAML comments when I convert to JSON?

Comments, anchors, and other YAML-only features are dropped because JSON has no way to represent them. The data values are preserved, but any human-facing notes in the YAML will not survive the round trip.

Why do I get an indentation or line error?

YAML is whitespace-sensitive and does not allow tabs for indentation. The tool reports the line number of the first problem it finds so you can fix the offending indentation, missing colon, or unbalanced quote quickly.

Can I choose the indentation of the output?

Yes. Use the indentation dropdown to switch between 2-space and 4-space output for both YAML and JSON, so the result matches your project's formatting conventions.

Is there a size limit?

There is no fixed limit imposed by the tool. Because everything runs locally, the practical ceiling is your device's available memory, which comfortably handles typical config files and API payloads.