JSON Formatter & Viewer
Format, validate, and visualize JSON instantly. Prettify, minify, sort keys, convert to YAML, and explore with a tree view.
How It Works
Parses a raw, minified string of JSON data and reconstructs it with proper indentation, line breaks, and syntax highlighting. It also validates the structure against RFC 8259.
Formula
JSON.stringify(JSON.parse(inputString), null, indentLevel)
The algorithm first parses the string into a native JavaScript object, checking for syntax errors. It then serializes it back into a string, adding spaces for indentation.
Worked Example
Formatting a minified JSON string
- Raw Input: `{"name":"John","age":30}`
- Parser verifies all keys are double-quoted and syntax is valid.
- Formatter applies 2-space indentation.
- Result: { "name": "John", "age": 30 }
Common Mistakes
✕
Using single quotes
✓
JSON strict specification requires double quotes (") for keys and string values. Single quotes (') will throw an error.
✕
Trailing commas
✓
Unlike standard JavaScript objects, JSON does not allow a comma after the final item in an array or object.
Frequently Asked Questions
Related Guide & Instructions
2026-07-14
How to Format, Validate, and Debug Complex JSON Data
Master JSON data syntax, discover techniques to locate syntax errors, and learn to prettify and minify data structures.
Read full guide →