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JSON Formatter
Paste JSON on the left — format, minify, or validate it on the right. Parse errors show line and column. Your data never leaves your browser.
Mode:
Indent:
JSON Input
Formatted Output
JSON Input
Formatted Output
How to use JSON Formatter
- 1
Paste JSON
Paste your JSON into the left CodeEditor. The right pane shows the formatted output live.
- 2
Pick a mode
Format pretty-prints, Minify strips whitespace, Validate just reports errors without changing the input.
- 3
Choose indentation
Pick two spaces, four spaces, or tab. Errors include line and column.
- 4
Copy or download
Use the copy button on the output, or download the formatted JSON.
Frequently asked questions
- Does this tool upload my JSON?
- No. Every parse, transform, and download runs entirely in your browser using JavaScript and Web Workers. The file never leaves your device — there is no upload endpoint and no server-side processing.
- Why does the parser flag my trailing comma as an error?
- JSON does not allow trailing commas. JSONC and JSON5 do, but they're separate formats — strip the trailing comma to make this strict-JSON tool happy.
- Can it handle huge JSON files?
- Yes for files that fit in browser memory. JSON parsing is single-pass, so the practical ceiling is similar to other in-browser tools — a few hundred megabytes typically.