JSON ↔ YAML Advanced Converter

Bidirectional conversion with multi-document YAML, flow vs block style, and browser-side validation.

Last reviewed: June 2026
Reviewed by , software engineer · last updated June 2026

New to this tool? Click here for instructions

Style: Indent: JSON indent:
JSON Input
YAML Output
Paste JSON or YAML above to convert.

How to Use the JSON to YAML Converter

Select JSON → YAML or YAML → JSON, paste your data into the input pane, and the output updates automatically. For JSON output you can choose two- or four-space indentation. For YAML output you can choose block style for readable config files or flow style for compact inline values.

Use Try Example to load a Kubernetes-style JSON sample in JSON mode or a small YAML config in YAML mode. Copy the converted output or download it as converted.yaml or converted.json.

When to Use the Tool in Real Workflows

This tool is useful when you are translating JSON examples into YAML configuration, checking how a YAML file will look as JSON, preparing snippets for Kubernetes or GitHub Actions documentation, or cleaning up generated config before pasting it into a repository.

How It Works

All conversion runs in local JavaScript. JSON → YAML mode parses the input with JSON.parse(), then emits YAML mappings, sequences, strings, numbers, booleans, and null values. YAML → JSON mode uses the page's built-in parser for common JSON-compatible YAML and serializes the result with JSON.stringify().

The page does not send your configuration to an external converter. The status bar reports how many documents and nodes were converted, which helps spot accidental multi-document input.

Tips, Edge Cases, or Limitations

1. Multi-document YAML: Separate documents with a line containing exactly ---. Multiple YAML documents convert to a JSON array.

2. Block vs flow style: Block style is easier to read and edit. Flow style is compact and closer to JSON syntax.

3. Parser scope: The local YAML parser supports common mappings, sequences, scalars, flow collections, comments, literal blocks, and simple aliases. It is not a complete replacement for a production YAML parser.

4. Type preservation: Strings that look like numbers or booleans may need quotes if you want them to stay strings.

5. Config review: Always validate production Kubernetes, CI, Docker, or Helm files with the toolchain that will actually run them.

Frequently Asked Questions

YAML (YAML Ain't Markup Language) is a human-readable data serialization standard. It is often used for configuration files and in applications where data is being stored or transmitted.
A multi-document YAML file contains multiple independent documents, each separated by a line containing exactly ---. This is common in DevOps configurations like Kubernetes manifests.
Block style uses newlines and indentation to represent structure, making it more readable for human-edited files. Flow style uses braces { } for objects and brackets [ ] for arrays, which looks exactly like JSON.
No, the tool performs the conversion client-side. Your data is never sent to a server, ensuring privacy and security.
The converter supports common JSON-compatible YAML structures: mappings, sequences, strings, numbers, booleans, nulls, multi-document separators, block output, and flow output. It is useful for quick config drafts, but it is not a complete YAML 1.2 parser.

Quick reference

JSON and YAML Converter Controls
Control Applies to What it changes Best use
JSON → YAML JSON input Parses JSON and emits YAML Turning API examples into config snippets
YAML → JSON YAML input Parses common YAML and emits formatted JSON Inspecting config data in JSON form
Block style YAML output Uses indentation and one key per line Human-edited configuration files
Flow style YAML output Uses braces and brackets Compact inline values
Indent controls Both directions Switches between 2 and 4 spaces Matching repository style
Download Converted output Saves .yaml or .json Moving a draft into a project

Example walk-through

Worked example: step-by-step

Step 1. Leave JSON → YAML selected and click Try Example. The input pane loads a nested deployment-style JSON object.

Step 2. Keep Style set to Block and Indent set to 2 spaces for readable YAML.

Step 3. The output updates immediately. A portion of the converted YAML looks like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  labels:
    app: web
    env: production
spec:
  replicas: 3

Step 4. Switch to YAML → JSON, click Try Example again, and the page converts the YAML sample into formatted JSON.

Step 5. Copy or download the result, then validate production configuration with the runtime that will consume it.