❯ JSON ↔ YAML Converter

How to use the JSON ↔ YAML converter

1. Pick a direction. JSON → YAML for converting API payloads to readable config. YAML → JSON for feeding YAML into systems that only speak JSON.
2. Paste your input. The left pane accepts JSON (or JSONC, if you toggle the option) or YAML depending on direction. The right pane shows the converted output live.
3. Choose block or flow. Block is the readable multi-line YAML. Flow is the compact inline form. Pick what your downstream tool expects.
4. Set indent and sort. 2 or 4 spaces. Toggle Sort keys when diffing two configurations whose key order differs.
5. Share or download. Copy share link round-trips the whole session via the URL hash. Download saves the result as data.yaml or data.json.

Why convert between JSON and YAML?

• Kubernetes: most manifests are YAML on disk but kubectl accepts JSON.
• GitHub Actions / GitLab CI: workflow files are YAML; intermediate scripts often produce JSON that needs converting.
• OpenAPI / Swagger: spec files exist in both forms; tools and editors pick one.
• VS Code / tsconfig: JSONC settings can be exported to YAML for documentation or audit.
• Helm charts: values.yaml ↔ JSON when integrating with external systems.

YAML gotchas this tool guards against

Quoting strings that look like other types

YAML coerces unquoted scalars aggressively. The classic example: country: NO parses as country: false under YAML 1.1 (“Norway problem”). This tool uses the YAML 1.2 JSON-compatible schema and quotes ambiguous strings on JSON → YAML output, so "NO" stays a string when you round-trip back.

Indentation

YAML uses spaces, not tabs. This tool emits spaces only. If you paste YAML with tabs, the parser will reject it with a clear line/column error.

Anchors and aliases

defaults: &defaults
  retries: 3
prod:
  <<: *defaults
  url: https://example.com

YAML → JSON expands anchors so the output JSON has the merged keys. JSON → YAML never emits anchors (every reference becomes a literal copy). This is the same behavior as kubectl apply and most CI systems.

Multi-document YAML

Files with --- separators (multiple documents in one file) are rejected. Split them and convert one at a time.

Example: Kubernetes Service

Input (JSON):

{
  "apiVersion": "v1",
  "kind": "Service",
  "metadata": { "name": "demo" },
  "spec": {
    "selector": { "app": "demo" },
    "ports": [{ "port": 80, "targetPort": 8080 }]
  }
}

Output (YAML, block style, 2-space indent):

apiVersion: v1
kind: Service
metadata:
  name: demo
spec:
  selector:
    app: demo
  ports:
    - port: 80
      targetPort: 8080

Round-tripping back to JSON returns the same object.

Privacy and security

The converter is a single HTML page with a small JavaScript bundle. Your input never leaves your device. The share link encodes state in the URL fragment (#…) — that part of a URL is not sent to servers. Verify in DevTools → Network: no outbound requests after the page loads.

Related tools

• JSON Formatter & Error Reviewer — validate and pretty-print JSON with line/column error pointing.
• JSON to CSV Converter — convert tabular JSON to CSV in your browser.
• Markdown ↔ HTML Converter — the same idea for prose formats.

Frequently asked questions