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JSON ↔ YAML Converter

Convert between JSON and YAML formats bidirectionally.

jsonyamlconvertconfig
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About the JSON ↔ YAML Converter

The JSON ↔ YAML Converter is a bidirectional translation tool for the two serialization formats that dominate modern configuration and infrastructure work. Paste valid JSON into the JSON input textarea and it instantly renders an equivalent YAML document with two-space indentation; switch to the YAML → JSON tab and paste YAML to receive a pretty-printed JSON object, also indented with two spaces. There is no Convert button to remember — every keystroke re-runs the conversion live, so you see the YAML representation of your nested objects, arrays, booleans, and numeric settings the moment your braces balance. When input is malformed, the tool never crashes or emits half-converted data: a red alert shows the exact parser message, a toast fires, and the output area stays empty until you fix the syntax. Stat chips track the active mode plus input and output byte sizes, and Clear and Load sample buttons on both tabs reset the workspace or drop in a ready-made document with nested config. This makes converting JSON to YAML for a Kubernetes manifest, or YAML to JSON for a Node.js config file, a matter of seconds rather than hand-editing.

JSON ↔ YAML Converter examples

Input
{
  "name": "Fernandes Labs",
  "tools": ["json", "yaml", "xml"],
  "version": 1,
  "open": true,
  "config": {
    "timeout": 30,
    "retries": 3
  }
}
Output
name: Fernandes Labs
tools:
  - json
  - yaml
  - xml
version: 1
open: true
config:
  timeout: 30
  retries: 3
Note: The built-in JSON sample on the JSON → YAML tab — nested objects become indented mappings, arrays become dash lists, and numbers stay unquoted.
Input
name: api-gateway
replicas: 3
image: nginx:1.25
ports:
  - 80
  - 443
Output
{
  "name": "api-gateway",
  "replicas": 3,
  "image": "nginx:1.25",
  "ports": [
    80,
    443
  ]
}
Note: On the YAML → JSON tab the same document round-trips to pretty-printed JSON with two-space indentation.
Input
{ "version": 1, }
Output
No YAML output — the red alert shows the JSON parse error and a toast reports Invalid JSON input until the trailing comma is removed.
Note: Malformed input never produces half-converted data; the output box stays empty until the syntax is fixed.

How to use the JSON ↔ YAML Converter

  1. 1

    Click the JSON → YAML tab, or YAML → JSON for the reverse direction.

  2. 2

    Paste your document into the input textarea — the sample is preloaded, so use Load sample to restore it anytime.

  3. 3

    Watch the output appear instantly in the result box below as you type.

  4. 4

    If a red alert appears, fix the reported syntax problem and the conversion resumes automatically.

  5. 5

    Use the download button in the result box to save converted.yaml (or converted.json).

Common use cases

  • Converting a JSON config file into a readable YAML document for a CI pipeline.
  • Turning an existing Kubernetes YAML manifest into JSON for a tool that only consumes JSON.
  • Quickly checking whether two config snippets represent the same data in different formats.
  • Generating YAML for GitHub Actions workflows from JSON fixtures.
  • Migrating settings between a Node.js project (JSON) and a Python or Ansible project (YAML).
  • Sanity-checking a hand-written YAML file by converting it to JSON and eyeballing the structure.

Best practices

  • Keep JSON input strictly valid — trailing commas and unquoted keys are legal in JavaScript but rejected by the parser here.
  • For YAML input, remember that tabs are not allowed for indentation; use spaces to avoid parse errors.
  • Use the Load sample button when you want a known-good starting document to compare against.
  • Round-trip critical configs (JSON → YAML → JSON) and diff the results to catch data loss before deployment.
  • Watch the Input bytes and Output bytes stats to spot accidental bloat from extra whitespace.
  • Download the output rather than copying from the page, since the file keeps exact indentation.

Tips

  • Start with the Load sample button to see a correct conversion in both directions before pasting your own data.
  • When a conversion fails, search the alert message — the parser errors are standard and widely documented.
  • Use the Mode stat to confirm which direction you are converting, especially after switching tabs quickly.
  • Convert before you edit: moving a config to YAML first often makes merge conflicts easier to review.

Frequently asked questions

Both tabs run a live conversion effect that fires on every keystroke, so your output is always in sync with the current input. This avoids stale results: you can never forget to click Convert because there is nothing to click. If the input is empty or invalid, the output area simply stays empty and shows guidance instead.

The JSON.parse call throws, and the tool surfaces the exact error message in a red alert plus a toast notification. No partial YAML is emitted. The moment you fix the syntax — for example removing a trailing comma — the conversion reruns and the output appears.

No. The YAML side parses a single document via js-yaml load. A multi-document stream separated by --- markers would only produce the first document, so split streams into separate conversions if you need all of them.

No. YAML comments are dropped during parsing, so converting YAML to JSON and back loses them. The conversion pipeline works on parsed data structures, not the original text.

Yes. JSON numbers stay numbers in YAML output and vice versa, as long as the parser can represent them. Very large integers may lose precision in JSON due to JavaScript number semantics, so treat IDs as strings when converting.

YAML output uses two-space indentation with a line width of 100, and JSON output is pretty-printed with two-space indentation via JSON.stringify. Both formats are therefore consistent and ready to paste into source control.

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