JSON to YAML Converter

1. 1

   Paste or upload JSON

   Paste JSON into the editor, or drop a .json, .ndjson or .jsonl file onto the page. Nothing is uploaded — the file is read on your device.

2. 2

   Choose the target parser

   Portable is the default and quotes every value that a YAML 1.1 or timestamp-resolving parser would read as a different type. Pick YAML 1.2 for minimal quoting, or quote every string when the consumer is unknown.

3. 3

   Set the layout

   Choose the indent, how nulls are written, and whether the document starts with ---. The preview updates as you change each one.

4. 4

   Convert and check the result

   Press Convert to YAML. The result is read back with an independent parser and compared to your original JSON, and the badge says whether every value survived.

5. 5

   Download or copy

   Download the .yaml file or copy it to the clipboard. Use the YAML to JSON tool for the reverse.

This free converter turns JSON into YAML on your device. Paste or upload JSON, pick the parser your YAML is written for, and the converter quotes exactly the values that would otherwise change type on the way out. Every result is read back with an independent parser and compared against your original JSON before it is offered to you. Invalid JSON is located to the character, with a caret and a route out.

• Quoting for a named parser — Choose YAML 1.2, portable, or quote every string. Portable is the default and is safe under PyYAML, js-yaml, Ruby Psych and Go.
• Round-trip verification — The YAML is re-read with an independent parser and compared value by value to your JSON. The badge names the first path that differs if any does.
• Readable multi-line strings — A string containing newlines is written as a block literal, so scripts, certificates and SQL stay readable instead of collapsing into escapes.
• NDJSON in, multi-document YAML out — One JSON value per line becomes one YAML document per line of input, separated by ---. Blank lines are skipped.
• Errors located on your device — Message, line, column, a caret under the exact character and what was expected there — identical in every browser rather than whatever the browser's own parser reports.
• Runs on your device, not our servers — The file is read, parsed, converted and verified locally. There is no upload step, so there is nothing to opt out of.

This is the setting that decides whether the conversion is correct, and it is the reason this tool exists. YAML has no single agreed way to read an unquoted word: the same file means different things to different parsers, and a converter that writes minimal quotes is betting on which one you will use.

• Portable (default) — Quotes the union of everything a YAML 1.2 core parser, a YAML 1.1 parser and a timestamp-resolving parser would re-type. Slightly more quotes; the same values everywhere.
• YAML 1.2 — Minimal quoting, matching the YAML 1.2 core schema. Correct if — and only if — whatever reads the file is a 1.2 parser with no timestamp resolution. The tool still counts and reports the values a 1.1 reader would change.
• Quote every string — Every string scalar is quoted. Verbose, unambiguous, and the right answer when you have no idea what will read the file.
• Who reads YAML 1.1 — PyYAML and therefore Ansible and SaltStack, Ruby's Psych, and a long tail of tooling built on them. It is not a legacy corner; it is most of the infrastructure world.

These are not exotic strings. They are the ones people actually store in configuration files, and each one comes back as a different type from a parser that has not been told otherwise. Portable mode quotes all of them; YAML 1.2 mode quotes only the first row and tells you how many of the rest it left alone.

• true, false, null, 12, 1.5, 0x1F — Re-typed by every parser, including YAML 1.2. Always quoted, in every mode.
• yes, no, on, off, y, n — Strings under YAML 1.2. Booleans under YAML 1.1 — so a config value of "no" becomes false in Ansible.
• 0755, 0644 — A file permission, and a leading-zero octal integer to a YAML 1.1 parser: 0755 becomes 493.
• 1:30, 12:30:45 — A duration or a timestamp to you; base-60 integers to a YAML 1.1 parser, which reads 1:30 as 90.
• 2024-01-01 — A date object to anything with timestamp resolution, including js-yaml's default schema, PyYAML and Go's yaml.v3.
• 1_000, 0b1010 — Strings by the letter of the 1.2 specification, integers to js-yaml. Quoted anyway, because the reader is what matters and not the specification.

The mapping is direct and the structure of your document is preserved exactly. Nothing is reordered, nothing is dropped, and no key is renamed.

• Objects — Indented key-value blocks. Key order is preserved unless you ask for sorted keys.
• Arrays — Dash-prefixed lists. A list inside a mapping can be indented or sit at the key's column.
• Empty object and empty array — Written {} and [] rather than left blank, because a blank value reads back as null and would silently change the shape.
• null — Written null by default, or as a tilde, or left empty. The empty form is used for mapping values only — see the note on layout below.
• Strings with newlines — Block literals, with the chomping indicator chosen from the trailing newlines so the string round-trips exactly.
• Keys — Quoted by the same rules as values. A key of "n" or "yes" is quoted, because an unquoted one becomes a boolean key in a YAML 1.1 reader.

A shell script inside a config map, a PEM certificate, a SQL statement — these are the values people most want to stay readable, and the ones a naive converter mangles into a single line of escapes.

• Block literals — A multi-line string is written after a | so the lines stay lines. The chomping indicator is chosen from the trailing newlines, so none are gained or lost.
• When a block cannot be used — A string whose first line is blank or indented, or that contains a carriage return or a control character, is quoted instead. Those cases need an explicit indentation indicator and getting one wrong is silent corruption.
• Wrapping long lines (Pro) — A wrap column folds long values with an escaped line break, which is the only wrapping form in YAML that is exactly reversible. Folded plain and folded block scalars are not, so a value that needs wrapping is quoted first.
• No accidental folding — With wrapping off — the default — long strings stay on one line rather than being folded, so nothing is reflowed on the way out.

NDJSON — also called JSON Lines — is one JSON value per line, and it is what log pipelines, database exports and jq -c produce. It is not valid JSON as a whole file, so most converters reject it.

• Detected two ways — By a .ndjson or .jsonl extension, and by content: a file that is not a single valid JSON document but whose non-blank lines each parse on their own.
• One document per record — Each value becomes its own YAML document, separated by ---, which is how a YAML stream is read back by every parser.
• A single-line array is not NDJSON — [1,2] is a valid JSON document, so it is converted as one. The single-document read is tried first for exactly this reason.
• A bad line stops the conversion — The line number is reported rather than producing a partly converted stream with silently dropped records.

None of these changes what the document means. All of them change how it reads, and the preview updates as you move each one.

• Indent — 1 to 8 spaces per nesting level. Two is the default and what most YAML tooling expects.
• Null style — null, a tilde, or empty. The empty form is used for mapping values only: an empty sequence entry at the end of a nested list is read differently by different parsers, so it is written as a tilde there.
• Document marker — Start the file with ---. Always emitted between documents in a multi-document stream, whatever this is set to.
• Sort keys (Pro) — Alphabetical keys, for diffs that do not move when a producer reorders its output.
• Quote style (Pro) — Single or double quotes where quoting is needed. Single quotes fall back to double for any string they cannot represent.
• Sequence indentation (Pro) — Indent a list under its key, or sit it at the key's column — the house style of Kubernetes manifests, and four fewer columns on every list.
• Multi-line style (Pro) — Readable block literals, or a single escaped double-quoted line.

Every other converter in this category hands you YAML and leaves you to find out later whether it still means what your JSON meant. This one checks, before you download anything.

• An independent reader — The result is parsed by a different implementation from the one that wrote it. A writer checked by its own reader proves nothing — the two would share any misunderstanding.
• Compared value by value — Against your original JSON, not against a re-serialised copy of it. Types are compared as well as values, so a string that came back as a date fails.
• The first difference is named — By path — /servers/3/started — with both types and both values, rather than a bare "verification failed" on a 40,000-line file.
• Read against the parser you chose — Verification uses the schema matching your target, so verified always means verified for the reader you said you were writing for.
• It can be turned off — It costs a second read of the document. On a large file with a known-good shape you may not want it; the setting is yours and the result is marked stale if you change it.

Powered by optimised processing algorithms.

YAML is the configuration format of the infrastructure world, and JSON is what almost everything emits. Converting between them is how data from an API, a database or an application ends up in a Kubernetes manifest, a Compose file, a GitHub Actions workflow or an Ansible playbook.

• Config workflows — Reuse JSON-shaped data in Kubernetes, Docker Compose, GitHub Actions, Ansible and anything else that reads YAML.
• Readability — YAML drops the braces and quotes, so a nested document is easier to read and to review in a pull request.
• Comments — YAML supports comments and JSON does not, so converting is often the first step in turning generated data into something a human will maintain.
• Correctness matters more here — A config file is executed. A version string that becomes a number, or a permission that becomes octal, does not fail loudly — it deploys.
• Privacy — It all runs on your device, not our servers, so an API response containing credentials or customer data is never uploaded.

• YAML to JSON
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• JSON Validator
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• JSON Viewer