Beautify / Pretty print
Readable 2-space indent for debugging and docs. Example: {\"a\":1} → multi-line with indent. Best for humans.
Free JSON tools — beautify, minify & validate offline
JSON formatter online — beautify, minify & validate JSON without upload
Format JSON online without uploading — beautify (pretty print), minify and validate JSON with precise line & column errors. Everything runs in your browser — no sign-up, nothing uploaded, works fully offline.
Drop a .json file here, or click to browse — your file never leaves your device
How to format JSON online without upload
Answer in 30 seconds: Paste JSON into the input or drop a .json file and click Format to beautify (pretty print). Click Minify to compress to one line, or Validate to check without reformatting. All parsing is local — your JSON never leaves your device.
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Paste or drop JSON
Paste JSON text or drag and drop a
.jsonfile. BOM and whitespace are handled automatically. Nothing is uploaded. -
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Beautify, minify or validate
Format pretty-prints with 2-space indent and shows precise line/column on error. Minify removes whitespace. Validate checks without changing text.
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Copy or download formatted JSON
Copy the result to clipboard or download as
fastcompiler-formatted.json. Works offline after page load.
Beautify vs minify vs validate — which to choose?
Direct answer: Beautify/format/pretty-print are the same — make JSON readable with indentation. Minify compresses to one line for APIs. Validate checks correctness without reformatting.
Minify / Compress
Single line, no whitespace. Use for API payloads, config files and smaller transfer size.
Validate / Lint
Checks syntax and shows line, column and snippet on error — fix missing commas, quotes or brackets fast.
Large file tip: for JSON >5MB, use Validate first to catch errors, then Format once valid. Everything stays local, so no upload limits.
Frequently asked questions
How do I format JSON online without upload?
Paste your JSON into the input and click Format. The tool parses locally and outputs pretty-printed JSON with 2-space indentation, or a precise error with line and column if invalid. Nothing is uploaded.
What is the difference between beautify, format and pretty print?
They are the same — beautify = format = pretty print indents JSON for readability. Minify is the opposite (compress to one line).
Can I minify or compress JSON?
Yes — click Minify to compress valid JSON to a single line for API payloads and config files.
How does validation work?
Click Validate to check without reformatting, or Format to validate and beautify. Errors show exact line, column and snippet.
Is my JSON uploaded anywhere?
No — parsing uses JSON.parse locally in your browser. Your JSON never leaves your device.
Does it handle large JSON files?
Yes — parsing is local, so no upload limits. Very large files (>10MB) may take a moment but stay offline.
Does it work offline?
Yes — runs entirely in your browser, works offline after page load.