YAML to JSON Converter

Converts in both directions and tells you what the conversion cost. The direction is detected from the input — a JSON document has to start with { or [ and parse as JSON, and almost nothing else does — so there is normally nothing to choose.

Why an unquoted NO stays a string here

This parses against the YAML 1.2 core schema, under which only true and false are booleans. Under the older 1.1 schema, y, yes, on and NO all resolve to booleans as well — which is how a list of country codes quietly turns Norway into false. A converter that retypes values is editing rather than converting, so the values you wrote are the values you get, and the ones whose type is easy to assume wrong are listed out so you can check instead of trusting.

Two more 1.1 habits the core schema drops: 0777 is the decimal number 777 here (1.1 read a leading zero as octal, 511; write 0o777 for octal), and 2026-09-20 stays a string rather than becoming a date object. If the consumer of your file is a 1.1 parser, such as PyYAML, it will read both differently.

What JSON cannot carry

Comments, anchors and aliases, multiple documents, and merge keys. Each is counted before the conversion runs and reported alongside the result rather than discarded in silence — in a manifest, the comment above a value is often the only surviving record of why it was set that way. The merge key is the surprising one: << is a YAML 1.1 extension rather than part of the core schema, so it comes through as a literal key holding the referenced map instead of being merged into its parent. .inf and .nan are counted too: JSON has no way to write them, so each becomes null.

Safe to paste something hostile

Only plain data is constructed — a tag that would build a function, a regular expression or a custom type is an error, and a __proto__ key stays an ordinary key. Aliases are the other risk: a few hundred bytes of nested anchors can expand to billions of values (the "billion laughs" document). The expanded size is measured before anything is written out, and a document that would pass a million values is refused rather than expanded.

Syntax, not schema

A clean result means the document parses. It does not mean it is a valid Kubernetes manifest, Compose file or pipeline definition — that needs the schema for a specific tool at a specific version, which this page does not carry and would go stale if it did. For the JSON side alone, the JSON Formatter reports duplicate keys and locates a syntax error by line and column.

The sample above converts to JSON with "region": "NO" and "version": "3.10" intact. Remove the quotes from "3.10" and it becomes the number 3.1, because unquoted they are the same number — which is why the ambiguous-value list exists.