JSON to YAML Converter

Convert valid JSON values to readable YAML while keeping formatting choices, duplicate object names, and JavaScript number-precision limits visible.

JSON input

Any valid JSON top-level value is accepted—not only objects.

0 lines

Indentation

Line width

Quote all stringsSort object keys

YAML output

The output is a new YAML serialization of the parsed JSON data, not a textual rewrite of the original JSON.

Converted YAML will appear here.

Conversion runs on the pasted text in your browser. No conversion API receives the JSON. Site-wide analytics or advertising scripts, if enabled, are separate from the conversion operation.

Converting the Data Is Easy; Preserving Its Meaning Is the Real Job

JSON has a deliberately small data model: objects, arrays, strings, numbers, booleans, and null. YAML can represent all of those values, so ordinary JSON usually converts cleanly. The input is parsed as JSON first and the resulting value is then serialized as YAML. RFC 8259 defines the JSON data-interchange format, including the interoperability warning around repeated object names and very large numbers.

That distinction matters. Indentation, quotes, line wrapping, and YAML scalar style are presentation choices created during output. They were not present in the parsed JSON data and do not change an object into a different object.

The Same JSON Value Can Have Several Reasonable YAML Presentations

JSON
{"name":"Sneha","roles":["editor","reviewer"],"active":true}

YAML
name: Sneha
roles:
  - editor
  - reviewer
active: true

A different serializer could quote "Sneha", use a flow sequence such as [editor, reviewer], or choose another indentation width while representing the same values. Do not use formatting differences alone to decide whether two YAML files carry different data.

Large Numbers Are the Most Important Browser-Side Conversion Trap

JavaScript parses JSON numbers into IEEE-754 Number values. Exact integer precision is guaranteed only through 9,007,199,254,740,991 in magnitude. A larger integer might be an order ID, database identifier, timestamp, or financial quantity that looks intact in the source but is rounded duringJSON.parse().

Integer tokens are checked before conversion so values beyond the safe-integer range do not quietly look exact after JSON.parse(). High-precision decimal and exponent forms are also called out. If a number overflows JavaScript's finite range entirely, conversion stops instead of silently turning the source into YAML infinity.

Duplicate JSON Object Names Are Already Lossy Before YAML Exists

JSON texts in the wild sometimes contain the same object name more than once. JavaScript's JSON parser keeps the later value, so by the time a normal object reaches YAML serialization the earlier value is gone. A source-level duplicate-name check keeps that loss visible instead of making the resulting YAML look lossless.

If duplicate names matter, fix the source or use a representation designed to preserve repeated entries, such as an array of name/value objects.

Why Some Strings Need Quotes Even When “Quote All Strings” Is Off

YAML plain scalars have syntax and type-resolution rules. A string that resembles a boolean, number, null value, indicator, or other special-looking scalar can need quotes so that loading the YAML produces the original string rather than a different type. The YAML serialization handles necessary quoting automatically. The YAML 1.2.2 specification is the useful reference when a plain scalar, quoted scalar, or type resolution rule behaves differently from what a configuration file appears to suggest.

The “Quote all strings” option is therefore a readability or policy choice, not a safety switch. It can make string intent visually obvious in generated configuration, but it also makes large YAML files noisier.

Sorting Keys Can Help Diffs—and Hurt Human Structure

JSON object member order is often used informally by humans even when an application's data semantics do not depend on it. Sorting keys can produce stable generated output and easier machine diffs, but it can also separate related configuration fields that were intentionally grouped together.

Leave sorting off when the source order communicates meaning to maintainers. Turn it on when deterministic alphabetical output is more useful than preserving that presentation order.

JSON Cannot Contain YAML-Only Features You May Expect to See

Comments, anchors, aliases, custom tags, YAML directives, block scalar styles, and document separators have no representation in ordinary JSON data. A JSON-to-YAML converter cannot invent those application-specific features reliably.

If the destination is a Kubernetes, Docker Compose, CI, or application configuration file, conversion gives you the data structure—not proof that the resulting keys satisfy that product's schema. Validate the generated YAML with the target system before deployment.

Unpaired UTF-16 surrogate escapes are another boundary worth stopping at. JSON's grammar can contain such sequences, but they do not name a Unicode scalar value and RFC 8259 notes that implementations can disagree about them. Conversion stops rather than emitting YAML whose Unicode meaning is not portable.