JSON Formatter & Validator
Format, validate, minify, sort keys, and inspect JSON. All processing is done locally in your browser.
Status
How to use
- Paste JSON in the left box, import a file, or click Load Sample.
- Choose indent size (0 = minify). Toggle Live validate for instant checks.
- Click Pretty, Minify, or Sort Keys. Output appears on the right.
- Copy or download the result as a
.jsonfile.
FAQ
Is my JSON sent to a server?
No. Everything runs locally in your browser for privacy and speed.
What does “Sort Keys” do?
It recursively sorts object keys alphabetically for stable diffs and readability. Arrays keep their order.
Why does validation fail?
Common issues: trailing commas, single quotes instead of double quotes, or unescaped characters. The error shows the first position that fails.
JSON Formatter & Validator — A Practical Guide
JSON (JavaScript Object Notation) is the lingua franca for data on the web — powering APIs, mobile apps, log pipelines, analytics, and configuration files. This guide explains why formatting and validation matter, how to avoid common pitfalls, and how to work faster with our tool.
What is JSON?
A lightweight text format for structured data: objects ({}), arrays ([]), strings, numbers, booleans, and null.
It’s language‑agnostic and easy to parse.
Why format?
Pretty formatting improves readability, code review, and diffs. Minified JSON is compact—ideal for network transfer and production configs.
Why validate?
Validation catches syntax issues early (trailing commas, wrong quotes, unescaped characters) before they break deployments or API calls.
Common JSON Errors & Quick Fixes
- Trailing comma:
{"a":1,}❌ → remove the last comma. - Single quotes:
{'a': 'b'}❌ → JSON requires double quotes:{"a":"b"}. - Unescaped characters: newline/tab inside strings must be escaped:
"line\\nnext". - Mixed top‑level values: Only one top‑level value allowed (object/array/string/number/etc.).
- Duplicate keys: Parsers keep the last one — use Sort Keys and review carefully.
Example: Pretty vs Minify vs Sort Keys
// Input
{"z":3,"a":{"c":2,"b":1},"list":[{"y":2,"x":1}]}
// Pretty (indent = 2)
{
"z": 3,
"a": {
"c": 2,
"b": 1
},
"list": [
{
"y": 2,
"x": 1
}
]
}
// Minify
{"z":3,"a":{"c":2,"b":1},"list":[{"y":2,"x":1}]}
// Sort Keys (deep)
{
"a": {
"b": 1,
"c": 2
},
"list": [
{
"x": 1,
"y": 2
}
],
"z": 3
}Performance Tips
- Indent size: smaller indent renders faster; indent
0(minify) is smallest. - Sort Keys: ideal for diffs but adds CPU on huge objects—use when you need stable ordering.
- Privacy: Everything is local; avoid pasting secrets if you can.
Troubleshooting Checklist
- “Invalid JSON” but looks fine: check for smart quotes or hidden characters; retype quotes.
- Large file stalls: try smaller chunks or lower indent.
- Clipboard blocked: some browsers need a user click before clipboard access; use the Download button.
Key Takeaways
- Pretty for humans, Minify for machines, Sort for stable diffs.
- Validate early to prevent API and deployment failures.
- Keep sensitive data local whenever possible.