Precise validation feedback
Find malformed JSON with useful parser diagnostics, line and column locations, and the affected line instead of a generic invalid message.
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Developer · Free
JSON Formatter & Validator
Beautify, minify, validate and inspect JSON with clear error locations, configurable indentation, recursive key sorting, a searchable tree, and document statistics.
JSON never leaves this browser
Input editor
Paste JSON or drop a .json file
21 lines·415 B
Valid JSON
Root: object · 5
1{2"project": "Toolkit",3"version": 1,4"active": true,5"tools": [6{7"name": "JSON Formatter",8"category": "Developer",9"features": [10"format",11"validate",12"inspect"13]14},15{16"name": "Scientific Calculator",17"category": "Calculators",18"features": [19"trigonometry",20"calculus",21"vectors"22]23}24],25"metadata": {26"private": true,27"serverUpload": null28}29}
Output 479 B
Nothing is uploaded. Formatting, validation, search and statistics run in your browser.⌘/Ctrl + Enter format · Tab indents
How it works
From raw JSON to readable, verified data.
The editor validates on every change. Once the structure is valid, choose a clean output format and inspect the document without switching tools.
- 01
Paste JSON or open a file
Paste JSON into the editor, drag in a .json file, or load the example. Files up to 10 MB are read directly by your browser.
- 02
Fix validation errors
See an immediate syntax result with the parser message and, where available, the exact line, column and source excerpt.
- 03
Format, inspect or export
Choose indentation, optionally sort object keys, beautify or minify, explore JSON paths in the tree, then copy or download the result.
Built for real payloads
More than a basic JSON beautifier.
Formatter and tree inspector
Pretty-print with two spaces, four spaces or tabs, sort keys recursively, and search keys, values or JSON-style paths in a collapsible tree.
Private document analysis
Calculate value counts, types, nesting depth and file size without uploading source data or formatted output to a server.
JSON formatting questions
Know exactly what the validator checks.
How do I format JSON online?+
Paste JSON into the input editor and choose Format JSON. Select two spaces, four spaces or tabs for indentation. You can also sort object keys recursively before copying or downloading the result.
How can I find an error in invalid JSON?+
The validator shows the parser error immediately and reports the line and column when the browser provides a source position. The affected source line is displayed beneath the editor to help locate the problem.
What are the most common JSON syntax errors?+
Common errors include trailing commas, single-quoted strings, unquoted property names, missing commas or colons, comments, and unescaped control characters. Standard JSON requires double quotes and does not allow comments.
Can I minify JSON?+
Yes. Minify removes indentation and unnecessary whitespace while preserving the parsed data. The output size is shown before you copy or download it.
Does sorting JSON keys change arrays?+
No. Recursive key sorting alphabetizes object property names but preserves array item order because array order is meaningful.
Is my JSON uploaded or stored?+
No. Validation, formatting, tree inspection and statistics run locally in your browser. Files are read with browser APIs and are not sent to a Toolkit server.
Can the tool validate a JSON Schema?+
This tool validates standard JSON syntax and structure. It does not currently validate a document against a custom JSON Schema or API contract.
How do I inspect a large nested JSON document?+
Open Tree view and expand only the objects or arrays you need. Search accepts property names, values and paths such as $.users to narrow the result list, and clicking a result copies its path.
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