YAML ↔ JSON Converter

Convert between YAML and JSON in either direction. 100% client-side.

YAML Input
JSON Output
Paste YAML above to convert it to JSON.

How to Use the YAML JSON Converter

  1. Choose a direction — select "YAML to JSON" or "JSON to YAML" using the chips above the editor.
  2. Paste your data into the input area on the left (or top on mobile).
  3. View the result — the converted output appears instantly on the right with validation feedback in the status bar.
  4. Copy or download — use the buttons above the output pane to copy to clipboard or download the result as a .json or .yaml file.

What This Tool Does

This converter transforms YAML data into JSON format and vice versa, entirely within your browser. The YAML parser is built from scratch without any external libraries. It handles the common YAML subset that covers over 90% of real-world configuration files, including nested objects, arrays, comments, quoted strings, booleans, numbers, null values, and multi-line strings. The JSON-to-YAML serializer produces clean, human-readable YAML with consistent 2-space indentation.

Features

  • Bidirectional conversion — switch between YAML-to-JSON and JSON-to-YAML with a single click
  • No external dependencies — the YAML parser is built from scratch, no CDN or library required
  • Validation with error messages — parse errors are displayed in the status bar with descriptive messages
  • Comment handling — YAML comments are stripped during conversion (JSON does not support comments)
  • Live conversion — output updates as you type with a 150ms debounce
  • Key count display — the status bar shows the number of top-level keys after successful conversion
  • Privacy — everything runs locally in your browser with zero server communication

YAML Syntax Basics

YAML (YAML Ain't Markup Language) uses indentation to represent structure. Key-value pairs are written as key: value, with the colon followed by a space. Nested objects are indicated by increased indentation. Arrays use the dash notation: each item starts with - followed by a space. Comments begin with # and extend to the end of the line. String values can be unquoted, single-quoted, or double-quoted. YAML recognizes boolean values (true, false, yes, no), null (null or ~), integers, and floating-point numbers automatically.

YAML vs JSON Comparison

JSON is the lingua franca of web APIs and is natively supported by every modern programming language. It has a strict syntax with curly braces for objects, square brackets for arrays, and mandatory double quotes for string keys and values. YAML, on the other hand, prioritizes human readability. It uses whitespace indentation instead of braces, supports comments for documentation, and allows unquoted strings. YAML is popular in DevOps tools like Docker Compose, Kubernetes, Ansible, and GitHub Actions. Since YAML is a superset of JSON, any valid JSON document is also valid YAML, but the reverse is not true due to YAML's additional features.

Common Use Cases

DevOps engineers frequently convert between YAML and JSON when working with CI/CD pipelines, infrastructure-as-code tools, and container orchestration platforms. A Kubernetes manifest written in YAML might need to be converted to JSON for an API call. A JSON response from a REST API might need to be converted to YAML for inclusion in a configuration file. Frontend developers convert JSON API responses to YAML for documentation. Backend developers convert YAML configuration files to JSON for programmatic processing. This tool makes these conversions instant and private.

Multi-Line Strings in YAML

YAML supports two special indicators for multi-line strings. The pipe character (|) preserves line breaks exactly as written, which is useful for code snippets, scripts, or formatted text. The greater-than character (>) folds line breaks into spaces, creating a single long line, which is useful for long descriptions or paragraphs. Both indicators can be followed by a chomping indicator: - to strip the final newline or + to keep it. These multi-line features have no equivalent in JSON, so the converter preserves the final string content in the JSON output. For more data format tools, try our JSON Formatter, CSV/JSON Converter, or .env Redactor.

Frequently Asked Questions

YAML and JSON are both data serialization formats, but they differ in syntax and use cases. JSON uses braces, brackets, and quotes with a strict syntax. YAML uses indentation and colons, making it more human-readable. YAML supports comments, multi-line strings, and anchors, while JSON is more widely supported in APIs and programming languages. YAML is a superset of JSON, meaning valid JSON is also valid YAML.
No. This YAML/JSON converter runs 100% in your browser using JavaScript. Your data never leaves your machine. There is no server-side processing, no logging, and no data collection.
This converter supports the most common YAML features including key-value pairs, nested objects via indentation, arrays with dash notation, inline arrays and objects, quoted and unquoted strings, numbers, booleans (true/false/yes/no), null values, multi-line strings with pipe (|) and fold (>) indicators, and comments. It covers the YAML subset used in over 90% of real-world configuration files.
Yes. Click the JSON to YAML chip to switch direction. The converter serializes JSON objects into clean, properly indented YAML with 2-space indentation. Arrays use dash notation, nested objects are indented, and strings that require quoting are handled automatically.
The most common YAML parsing errors are inconsistent indentation (mixing tabs and spaces), missing colons after keys, incorrect list formatting, and unquoted strings that look like other types. YAML is indentation-sensitive, so make sure you use consistent spacing. The error message shown in the status bar will help you identify the exact issue.