JSON ↔ YAML Converter
Convert JSON and YAML 1.2 locally with explicit direction, precision checks and clear unsupported-feature errors.
Input
Output
Choose a direction and enter one document. Switching direction clears the workspace.
One converter, two directions.
Choose JSON → YAML or YAML → JSON, enter one document and select Convert. Changing direction clears the workspace. Maps, arrays, Unicode strings, multiline strings, finite numbers, booleans and null are supported. Generated JSON uses the same token-preserving formatter as JSON Formatter.
Data is more portable than syntax.
YAML 1.2 core data is accepted. Comments, scalar styles, unused anchor names and numeric spelling are not retained. Dates are strings, not constructed date objects. JSON object keys must be strings; quote numeric-looking YAML keys. Duplicate keys, aliases, merge keys, non-core tags and multiple documents are rejected explicitly. No executable tags or arbitrary object construction are enabled.
Precision is a requirement.
Integer values use exact decimal tokens and BigInt where conversion requires it. Decimals that would change meaning through JavaScript numeric conversion are rejected instead of rounded. Infinity and NaN cannot become JSON numbers. Quote a value yourself only if a string is appropriate for your data contract.
Local, bounded conversion.
Both directions run in a local terminable worker: 32 KiB UTF-8 input, 32 nesting levels, 4,000 values, 128 KiB output and a two-second processing deadline. Cancel, edits, Reset and navigation stop pending work. No content leaves your browser, is logged or saved. Explicit copies/downloads remain outside the workspace after Reset.