JSON Formatter Online
Format JSON online with 2- or 4-space indentation, validate syntax on click, or minify JSON. Copy the result. Data stays in your browser.
Your files stay in the browser. Nothing is uploaded.
Waiting for input
Use cases and practical choices
Developers can inspect responses, testers can review request payloads, and implementation or operations teams can read exported JSON configuration. Readability is only the first step: field meaning, intended sharing scope and destination validation rules still require separate review.
Format, validate and minify JSON with an example
Paste JSON and choose the format button for four-space indentation or the two-space option. Minify removes formatting whitespace. Invalid JSON produces a syntax error when you click a button. Comments, trailing commas and single-quoted keys are not valid JSON.
{"name":"Toolbox.Hub","enabled":true,"items":[1,2]}Check data before using the formatted output
Formatting uses JavaScript JSON.parse and JSON.stringify. Duplicate object keys are collapsed, and integers beyond JavaScript’s safe range can lose precision. Keep large numeric identifiers in strings. This formatter does not validate against a JSON Schema.
- Base64 & URL — decode Base64 text before inspecting a JSON payload
- WebSocket debugger — send a JSON message to a WebSocket endpoint
Beautify, minify, and validate JSON
- Format JSON with 2- or 4-space indentation
- Validate JSON syntax when formatting or minifying
- Minify JSON and copy the result
How to format JSON
- Paste JSON such as {"name":"demo","enabled":true}. Keys and strings need double quotes; a JavaScript object containing comments is not valid JSON.
- Choose regular beautify, two-space beautify or minify. Regular formatting uses four spaces; minification removes formatting whitespace. Validation runs when you click.
- When a syntax error appears, inspect brackets, quotes, commas and unescaped line breaks, then retry. The page does not provide a tree editor, automatic repair or JSON Schema validation.
- Copy only after checking the values. Represent large identifiers as strings and retain the raw source to detect numeric-precision or duplicate-key changes.
JSON formatter FAQ
How do formatting, syntax validation and Schema validation differ?
Formatting makes valid JSON readable, while minification removes layout whitespace. Syntax validation only checks whether JSON.parse can parse the input. It does not verify required fields, business values or an API’s type contract. Passing this page’s validation does not establish that the data is correct.
Why is content copied from a log or API response invalid?
Common causes include log prefixes, single quotes, trailing commas, comments or unescaped line breaks inside strings. Isolate the complete JSON portion and inspect the error. The tool reports parse failures but does not promise clickable line-level diagnostics or automatic repair.
Can formatting change large numbers or duplicate fields?
Yes. Integers beyond JavaScript’s safe range can lose precision, and duplicate object keys collapse during parsing. Use strings for long order or device identifiers. Reserialized output should not be treated as a character-for-character preserved copy when duplicate keys or original numeric notation matter.
Can it export spreadsheets, edit a tree or repair data?
No. This page offers formatting, minification, syntax parsing and copying, without spreadsheet export, tree interaction or structural repair. It helps developers, testers and operational users inspect payloads, but destination-specific field checks are still required before importing data.