What does Fix JSON repair?

Trailing commas, // and /* */ comments, single-quoted strings, unquoted keys, smart quotes, NaN / Infinity / undefined, Python True / False / None, hex numbers, missing closing brackets and JSON wrapped in Markdown fences or prose. Each change is listed so you can review it.

Which query syntaxes are supported?

JSONPath (starts with $): child, wildcard, recursive descent, slices, unions and filters such as $.items[?(@.price > 10)]. jq-style (starts with .): paths, .[], pipes, select, map, keys, length, sort_by, to_entries, object and array construction and more. Variables, reduce and def are not supported.

What does Unescaped mode do?

It takes a JSON document that was stringified into a string (for example a JSON payload stored inside another JSON field) and unwraps it, repeatedly if it was double-encoded, then pretty-prints the inner document.

Can I format very large JSON files?

Yes. The tool handles files up to tens of megabytes, limited only by your browser's memory. Syntax highlighting and the tree view cap themselves on very large documents to stay responsive.

JSON Formatter

Format and beautify JSON instantly in your browser. Switch between pretty, minified, sorted, escaped and unescaped output, explore a collapsible tree, run JSONPath or jq-style queries, and repair almost-JSON (trailing commas, comments, single quotes, unquoted keys) with one click. Copy the result as a JavaScript object, Python dict, TypeScript interface or Go struct. Errors show the exact line and column. Runs entirely client-side.

Runs locally in your browser

For large JSON, open fullscreen to use the whole screen

JSON input

0 chars · 1 line

⌘ Enter re-run · ⌘ S download

Pretty

Output will appear here…

JSON Validator

Validate JSON syntax and JSON Schema, catch duplicate keys and precision loss, check NDJSON line by line.

JSON Minifier

Minify JSON, strip nulls, measure gzip size and encode as Base64 or URL-safe text.

JSON to YAML

Convert JSON into clean YAML with control over quoting, wrapping, anchors and multi-document output.

JSON Path Finder

Explore JSON as a tree, click any value to copy its path in 7 syntaxes, and evaluate JSONPath or jq queries.

JSON Diff

Compare two JSON documents side by side, ignore keys, match arrays by id and export JSON Patch or Merge Patch.

How to use JSON Formatter

1Paste or upload JSON, or load the sample. Your last input is remembered in this browser.
2Pick an output mode: Pretty, Minified, Sorted (A→Z or Z→A), Escaped, Unescaped, Tree or Query.
3If the input is invalid, press Fix JSON to repair trailing commas, comments, quotes and missing brackets, then review the change list.
4Use Copy as to export the document as a JS object, Python dict, TypeScript interface, Go struct or JSON.parse string.
5Press ⌘ Enter to re-run, ⌘ S to download, or Copy link to share the exact state.

About JSON Formatter

JSON Formatter is part of FizzKit — a collection of focused developer and ad-tech tools. Because everything runs locally, it works offline once loaded and never exposes your data to a remote server.

Frequently asked questions

No. FizzKit formats JSON entirely in your browser using the native JSON parser. Nothing is uploaded or logged. The last input is stored only in your browser's local storage.

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