Paste or drop
Text, a .json file, or a URL response you pasted. Large files are parsed in a worker.
Developer
JSON Formatter, Validator & Tree Viewer
Paste or drop JSON of any size. Errors are reported with line and column and the offending text; valid JSON can be pretty-printed with a chosen indent, minified, sorted by key, viewed as a collapsible tree with copyable paths, and queried with a dotted path or a simple JSONPath expression.
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How it works
Fix and format
The error message names the position; common mistakes (trailing commas, single quotes, comments) can be auto-repaired with one click, and the repair is shown.
Explore and export
Tree view with paths, a query box, and download or copy of the result.
Formats, limits and the numbers that matter
Repairs
Trailing commas, single-quoted strings, unquoted keys, // and /* */ comments, NaN and Infinity. Each repair is listed so you know what changed.
Paths
Click any tree node to copy its path in dot notation and in JSONPath; the query box accepts both.
Size
Tens of megabytes format fine; the tree view virtualises rows so 100k-element arrays stay responsive.
Common questions
Does it keep key order?
Yes unless you choose sort keys; numbers keep their original text where possible so 1.10 does not become 1.1.
Can I diff two JSON documents?
Use the Diff Checker with JSON mode, which normalises formatting before comparing.
Is anything uploaded?
No; the page does all the work.