JSON Formatter & Validator
Pretty-print, minify, validate, and debug JSON with line-by-line error detection and size statistics.
JSON Formatter & Validator
Pretty-print, minify, validate, and check JSON syntax errors locally.
What is the JSON Formatter & Validator?
The JSON Formatter & Validator is a fast, 100% private in-browser utility for formatting, minifying, and syntax-checking JSON (JavaScript Object Notation) data. Whether you are inspecting an API response, cleaning up configuration files, or debugging a payload, this tool gives you instant feedback with exact line numbers for syntax errors.
JavaScript Object Notation (JSON) has become the global standard data format for web APIs, microservice communication, config management, and database storage (PostgreSQL JSONB, MongoDB). However, unformatted JSON (minified strings without line breaks) is virtually unreadable for human developers, while invalid syntax (missing quotes, trailing commas, single quotes) causes silent failures or crashes.
100% Client-Side Privacy
Unlike many web-based JSON formatters that upload your data to remote servers, our tool processes all JSON locally inside your browser using V8 JavaScript engine parsing. This means API tokens, database keys, customer PII, and internal configurations contained within your JSON payload never leave your machine.
Key Features
- Pretty Print: Format JSON with 2-space or 4-space indentation for maximum readability.
- Minify / Compact: Remove all whitespace and line breaks to compress JSON payload size for network transfer or storage.
- Line & Column Error Location: When JSON parsing fails, receive exact line and character positions with clear error descriptions.
- Size & Statistics: Instantly see raw size in bytes, minified size, key count, array length, and compression ratio.
- Tree & Code Views: Switch between formatted raw code and interactive key-value tree viewer.
- One-Click Copy & Download: Copy formatted result to clipboard or download as a `.json` file.
How Does the JSON Formatter & Validator Work?
1. Paste your raw JSON into the input code editor.
2. Click Format (2 spaces or 4 spaces) to pretty-print with indentation.
3. Click Minify to strip all unnecessary whitespace.
4. View Validation Status: A green badge indicates valid JSON; a red badge highlights syntax errors with exact line numbers.
5. Inspect Stats: Check byte size, minified savings percentage, and node count.
6. Copy or Download: Click Copy to Clipboard or Download .json file.
Formula & Calculation Method
Compression Savings %:
Savings = ((Raw Bytes - Minified Bytes) / Raw Bytes) Ã 100
Syntax Validation:
Executed via native `JSON.parse(input)`. Errors caught via `try...catch` with line number extraction via string index parsing.
Example Calculation
Example JSON String:
`{"name":"ProCalc","type":"Developer Tools","active":true,"version":2.0}`
- Formatted (2 spaces):
```json
{
"name": "ProCalc",
"type": "Developer Tools",
"active": true,
"version": 2.0
}
```
- Raw Size: 76 bytes
- Minified Size: 63 bytes
- Compression Savings: 17.1%
Frequently Asked Questions
**Compression Savings %:** Savings = ((Raw Bytes - Minified Bytes) / Raw Bytes) Ã 100 **Syntax Validation:** Executed via native `JSON.parse(input)`. Errors caught via `try...catch` with line number extraction via string index parsing.
Disclaimer: All developer utilities run 100% locally in your browser. None of your code, tokens, passwords, or input data are sent to or stored on remote servers.