JSON to YAML Converter

Convert JSON to YAML and YAML back to JSON in one click. Everything runs locally in your browser — nothing is ever uploaded.

JSON to YAML Converter features

Two-Way Conversion

Convert JSON to YAML and YAML to JSON with a single Direction toggle — no separate tools needed.

One-Click Swap

The Swap button instantly reverses the conversion direction so you can round-trip data fast.

Syntax Highlighting

JSON output is color-highlighted for readability, while YAML is rendered as clean plain text.

Clear Error Messages

Invalid JSON or YAML returns a precise parser message so you can pinpoint and fix the problem.

100% Private

All conversion runs locally in your browser. Your data is never uploaded or stored on any server.

Works Offline

Once the page has loaded, the converter keeps working without an internet connection.

Overview

JSON (JavaScript Object Notation) and YAML (YAML Ain't Markup Language) are two of the most common formats for configuration files and structured data. JSON uses braces and brackets — {"name": "Formatly", "tools": ["json", "yaml"]} — while YAML uses indentation and is designed to be easy for humans to read and edit.

This JSON to YAML converter translates data between the two formats in both directions. With the Direction toggle set to JSON → YAML, it parses your JSON and renders the equivalent YAML. Switch the toggle to YAML → JSON and it parses your YAML and produces pretty-printed, syntax-highlighted JSON instead.

The conversion is powered by js-yaml, a widely used and well-tested YAML library. YAML output is generated with two-space indentation and no line-wrapping, so long values stay intact on a single line. The structure, keys, and values of your data are preserved exactly across the round trip.

Because every step happens inside your browser using JavaScript, your data never leaves your device. There is no server call, no upload, and no logging — making this safe for configs, secrets, and proprietary data.

How to use the JSON to YAML Converter

Paste your JSON or YAML into the input box.
Set the Direction toggle to JSON → YAML or YAML → JSON to match your input.
Read the converted result in the output panel — JSON output is syntax-highlighted, YAML output is shown as plain text.
Use the Swap button to flip the direction and feed the output back as new input.
Copy the converted output to use in your config files or code.
Fix any reported syntax error in your input and the output updates automatically.

Good to Know

A few things worth keeping in mind when converting between JSON and YAML:

YAML is a superset of JSON. Valid JSON is also valid YAML, but YAML supports features (anchors, comments, multiple documents) that have no JSON equivalent.
Comments are not preserved. Converting YAML to JSON drops comments, because JSON has no comment syntax.
YAML output excludes references. The converter generates YAML without anchors or aliases, so repeated structures are written out in full.
Long lines are not wrapped. YAML output keeps long values on a single line rather than folding them, which avoids ambiguity but can produce wide lines.

Private by design

Every byte you paste into the JSON to YAML Converter is processed locally in your browser. Formatly makes no network request with your data, logs nothing, and stores nothing on any server — so it is safe for API responses, tokens, configuration and other sensitive content. Your most recent input and theme are saved only in your own browser's local storage.

JSON to YAML Converter FAQ

Is my data uploaded to a server?

No. This converter runs entirely in your browser using JavaScript. Your JSON and YAML are processed locally on your device and are never uploaded, transmitted, or stored on any server.

Does the converter work offline?

Yes. After the page has finished loading, all conversion happens client-side, so you can convert JSON to YAML and back even without an internet connection.

What is the difference between JSON and YAML?

Both represent the same kinds of structured data, but the syntax differs. JSON uses braces, brackets, and quotes — for example {"key": "value"} — and is compact. YAML uses indentation instead of brackets and is designed to be easier for people to read and write, which is why it is popular for configuration files.

Can I convert YAML back to JSON?

Yes. Set the Direction toggle to YAML → JSON (or click the Swap button). The tool parses your YAML and outputs pretty-printed, syntax-highlighted JSON.

What happens if my input is invalid?

The converter shows a clear error message from the parser. Invalid JSON reports the parse problem, and invalid YAML reports the js-yaml error, so you can locate and correct the issue in your input.

Will the conversion change my data?

No values are altered. Keys, values, arrays, and nesting are preserved across the conversion. YAML output uses two-space indentation and does not wrap long lines, so even lengthy strings stay intact.

Is there a size limit?

There is no fixed limit. Because conversion happens in your browser, performance depends on your device's memory and CPU. Typical config files and API payloads convert instantly.