What is a JSON formatter?
A JSON formatter is a tool that transforms JSON data between different representations:
- Beautify / Pretty-print: Adds indentation, line breaks and spaces for human readability
- Minify / Compact: Removes all unnecessary whitespace to reduce size (ideal for transmission)
- Validate: Checks that syntax complies with RFC 8259 standard
- Sort keys: Alphabetically reorders each object’s keys for deterministic comparison
Why use this tool?
| Use Case | Recommended Action |
|---|---|
| Read compressed API response | Format |
| Send payload in HTTP request | Minify |
| Verify if JSON is valid | Validate |
| Compare two JSONs in version control | Sort keys + Format |
| Clean config file | Format + Sort keys |
| Debug parsing error | Validate (shows exact error position) |
JSON Standard (RFC 8259)
This tool follows the strict standard:
| Feature | Supported | Notes |
|---|---|---|
Objects {} |
✅ | Keys in double quotes |
Arrays [] |
✅ | |
Strings "" |
✅ | Unicode escape \uXXXX |
| Numbers | ✅ | Integers, decimals, scientific notation |
| Booleans | ✅ | true / false |
null |
✅ | |
| Comments | ❌ | // or /* */ not allowed |
| Trailing commas | ❌ | { "a": 1, } invalid |
| Unquoted keys | ❌ | { a: 1 } invalid |
| Single quotes | ❌ | { 'a': 1 } invalid |
If your JSON has comments or trailing commas, it’s JSON5 or a variant, not standard JSON. Remove them before using this tool.
Precise Error Detection
When JSON is invalid, the tool:
- Attempts to parse with native
JSON.parse() - Catches the error
SyntaxError - Extracts position (line and column) from error message
- Highlights the problematic zone in the editor
- Shows readable message: “Expected ‘,’ at line 5, column 12”
This saves hours of manual searching for missing commas, unclosed braces or badly escaped strings.
Total Privacy: Zero Network
- ✅ 100% client:
JSON.parse(),JSON.stringify()and string manipulation in your browser - ✅ No telemetry: No analytics, tracking or server logs
- ✅ Offline-ready: Works if you save page as HTML (Service Worker)
- ✅ No size limit: Only limited by browser memory (~10-50 MB typical)
Keyboard Shortcuts
| Action | Windows/Linux | Mac |
|---|---|---|
| Format | Ctrl + Enter |
Cmd + Enter |
| Minify | Ctrl + Shift + M |
Cmd + Shift + M |
| Validate | Ctrl + Shift + V |
Cmd + Shift + V |
| Sort keys | Ctrl + Shift + S |
Cmd + Shift + S |
| Copy result | Ctrl + Shift + C |
Cmd + Shift + C |
| Clear | Ctrl + Shift + X |
Cmd + Shift + X |
Try the formatter now
Format, minify, validate and sort your JSON instantly. Private, free and no sign-up.
Format and validate your JSON instantly.