How to Format JSON: Complete Guide with Examples
2026-05-23
Quick Answer
Quick Answer: The fastest way to format JSON is to paste it into a JSON Formatter that validates and pretty-prints in one step. In code, use JSON.stringify(obj, null, 2) in JavaScript. Details below.
What is JSON formatting?
JSON formatting (pretty-printing) adds indentation and line breaks so nested objects are readable. Minifying does the opposite—removes whitespace for smaller payloads.
Why format JSON?
- Debugging: Logs and API responses are easier to scan when indented.
- Code review: Diffs on formatted JSON highlight real data changes.
- Documentation: Examples in README files should be readable.
Three ways to format JSON
1. Online formatter (fastest for ad-hoc work)
Use our JSON Formatter: paste, click Format, copy the result. Nothing leaves your browser.
2. JavaScript
const obj = { name: "DevToolbox", active: true };
console.log(JSON.stringify(obj, null, 2));
3. CLI with jq
echo '{"a":1}' | jq .
Common errors and fixes
| Error | Fix |
|---|---|
| Trailing comma | Remove comma after last property |
| Single quotes | JSON requires double quotes for strings |
| Comments | Strip // lines—JSON has no comments |
Pro tip: If JSON.parse fails near position 4000, your file may be one long line—format first, then search for the error line.
Try It Yourself
Ready to format your JSON? Try our free JSON Formatter →
Frequently Asked Questions
How do I pretty print JSON in JavaScript?
Use JSON.stringify(value, null, 2) for 2-space indentation, or 4 for wider indent.
Can JSON have comments?
Standard JSON does not support comments. Use JSON5 in tools that explicitly support it, or remove comments before parsing.
Is minified JSON valid?
Yes. Minification only removes optional whitespace; data stays the same.