YAML to JSON Converter

YAML is pleasant to write by hand, but APIs, JavaScript code and many tools want JSON. This converter reads YAML with the js-yaml parser — anchors and aliases are expanded, merge keys (<<: *defaults) are applied, and files with several --- documents are supported — and writes standard JSON with the indentation you choose. Everything runs in your browser.

How to use this tool

1. Paste your YAML (a Kubernetes manifest, a CI file, an OpenAPI spec…).
2. Pick the JSON indentation, or Minified for a single line.
3. Choose what happens with several documents: an array, the first one only, or one JSON per line.
4. Decide whether dates stay as written or become ISO 8601 timestamps, then copy the JSON.

Formula

mapping → object · sequence → array · scalar → string, number, true/false or null

Plain scalars are typed by the YAML 1.2 core rules: true/false, null/~, integers (including 0x1F and 0o14) and floats. Words such as yes, no and on stay strings — they were booleans only in the old YAML 1.1. .inf and .nan become null because JSON cannot store them, and !!binary data becomes a Base64 string.

Example

The default sample defines defaults: &defaults with timeout 30 and retries 2, then production: <<: *defaults with timeout 60. In the JSON, production becomes {"timeout": 60, "retries": 2}: the merge copies both keys and the local timeout wins. enabled: yes stays the string "yes", and released: 2026-03-01 stays "2026-03-01" unless you choose ISO conversion, which gives "2026-03-01T00:00:00.000Z".