JSON Formatter
Format, validate, and explore JSON. Clear structure, precise data, all in your browser.
How to use JSON Formatter
- Paste your JSON, open or drop a JSON file up to 2 MB, or load the sample to try it.
- Auto-format previews your JSON as you type. Choose 2 or 4 spaces, or use Minify, Validate, Escape, and Unescape from the toolbar.
- Keep escapes controls how string values are displayed. Turn it off to read escaped quotes and other characters inside values such as PageData. Keys stay unchanged; copy and download retain valid JSON.
- Switch between highlighted code and a collapsible tree. Use the reported line and column to locate syntax errors.
- Copy or download the result. Choose Use as input to continue working with transformed JSON. Press Ctrl or Command + Enter to format.
What is JSON Formatter?
JSON stores data as objects, arrays, strings, numbers, booleans, and null. Formatting adds indentation so nested data is easier to inspect. Minifying removes unnecessary whitespace; validation checks whether the input follows JSON syntax. These actions run locally in your browser.
- Live syntax validation, error locations, and automatic formatting
- Highlighted code with line numbers, line wrapping, and a collapsible tree view
- Format, minify, escape, and unescape without losing large numbers or duplicate keys
- Keep or hide escapes inside string values in code and tree views
- Local file import, drag and drop, clipboard copy, and JSON download
Preserve the numbers you received
For example, {"orderId":9007199254740993} contains an integer beyond JavaScript’s safe integer range. ADEMN formats the original number text rather than parsing and rewriting it as an ordinary Number, so its digits are retained. Use a quoted identifier when exact characters need to survive other systems as well.
Duplicate object keys are preserved for inspection. If a payload contains two status fields, formatting shows both, but another parser may choose one. Confirm the intended value in the source system before using that data.
Read nested JSON without changing a field’s type
A string field can contain serialized JSON. Keep escapes controls how that value is displayed; disabling it does not turn the string into an object or array. The decoded reading view may contain quotes or line breaks, while copy, download, and Use as input keep valid JSON text.
Use the sample’s PageData field to compare both views. Validate inner contents separately when needed, and check the receiving API’s expected field type. Syntax validation does not validate a JSON Schema or repair a business rule.
A practical example
{"name":"ADEMN","tools":["JSON Formatter","Word Counter"],"free":true}{
"name": "ADEMN",
"tools": [
"JSON Formatter",
"Word Counter"
],
"free": true
}Learn a little more
How to format and validate JSONFrequently asked questions
What does Keep escapes do?
When checked, string values show their original escape sequences. Uncheck it to display the decoded content of each value, including quotes inside a JSON string such as PageData. Keys are unchanged, and JSON-looking strings remain strings. This is a reading view: decoded quotes or line breaks may not form valid JSON text. Copy, download, and Use as input retain valid JSON with the required escapes. The separate Escape and Unescape actions encode or decode an outer quoted JSON string.
Is my JSON uploaded?
No. Formatting and validation run in your browser. The tool does not send the text you enter to a server.
Why is my JSON invalid?
Common causes include trailing commas, unquoted property names, single quotes, and comments. JSON requires double-quoted strings and does not allow comments or trailing commas.
Does this tool validate a JSON schema?
No. It checks JSON syntax. It does not check whether particular fields exist or whether your data matches a JSON Schema or an API contract.
Can I use this for large numeric IDs?
Yes. The formatter preserves the original number text instead of rewriting parsed numeric values. Other JavaScript tools may round large numbers when parsing them, so use quoted strings for identifiers when exact precision must survive across systems.