Developer utility

JSON Formatter Online

Paste JSON and instantly pretty print it for readability, minify it for storage, sort keys for comparison, or escape it for embedding — all processed locally in your browser with clear parse error messages and no server upload.

How it works

Paste JSON to pretty print, validate, minify, sort keys or escape strings instantly. Processing runs in your browser and syntax errors are shown without uploading the payload.

Paste JSON or an escaped JSON string.
Choose pretty print, minify, sort, escape or unescape.
Copy or download the processed output.

Result

Fill in the fields to see the result

The processed output appears here after you run the tool.

Instant validation and error detection

The browser parses the input immediately and shows the exact character or line where the syntax breaks — no server request needed.

Five formatting modes

Pretty print adds readable indentation; minify removes whitespace; sort keys alphabetizes fields for diffing; escape and unescape handle JSON-inside-JSON use cases.

Debugging tip

If parsing fails, reduce the payload to the smallest failing sample and look for unmatched brackets, trailing commas or unescaped characters.

Common use cases

Read and debug API responses with readable indentation.
Minify JSON before storing or embedding in code.
Find and fix parse errors with inline error messages.
Sort keys alphabetically for stable diffs and reviews.

Limitations

Comments are not valid JSON and will cause a parse error.
The tool highlights the error position but does not auto-fix broken syntax.
Sensitive payloads should be handled carefully even when processing is local.

Frequently asked questions

Does this support JSON with comments?

No. JSON comments (// or /* */) are not part of the JSON standard and will cause a parse error.

Is my JSON uploaded to a server?

No. All formatting and validation runs locally in your browser.

Can I sort object keys alphabetically?

Yes. Use the "Sort keys" mode to get a stable key order that makes diffs and reviews easier.

What does the minify mode do?

It removes all whitespace from the JSON, producing the shortest possible representation for storage or embedding.

Can I format large JSON files?

Yes, but very large payloads can slow down browser processing. For sensitive data, prefer using a local CLI tool.

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