YAML ↔ JSON Converter

What is YAML ↔ JSON Converter?

YAML ↔ JSON Converter is a free online tool for bidirectional conversion between YAML and JSON. YAML (YAML Ain't Markup Language) is the human-friendly superset of JSON used by Docker Compose, Kubernetes, GitHub Actions, and countless other config ecosystems — while JSON remains the lingua franca of APIs and machines. Moving between the two is a daily chore for developers, and doing it by hand is error-prone: indentation slips, unquoted strings, and type coercion surprises lurk everywhere. This tool converts instantly in either direction and validates the input before converting, so mistakes surface immediately.

Features

  • YAML → JSON — Parse YAML and emit clean, indented JSON
  • JSON → YAML — Serialize any JSON document to idiomatic YAML
  • Validation — Both directions validate first, with errors reported at exact line and column positions
  • Configurable indentation — Choose 2 or 4 spaces for the output
  • Structure preservation — Nested maps, lists, scalars, nulls, and multi-line strings survive the round trip
  • Duplicate key detection — YAML documents with repeated keys are flagged instead of silently accepted

How to use

Paste YAML or JSON into the input panel and pick the conversion direction. The converted output appears live as you type. Use the swap button to flip the output back into the input and convert the other way — handy for quick round-trip checks. Choose your indentation with the selector, then copy the result with one click.

Privacy

All conversion happens entirely in your browser. Your configuration files and data are never uploaded, logged, or sent to any server.

Read the full YAML ↔ JSON Converter guide and the YAML ↔ JSON Converter API reference.