JSON Formatter & Validator
Beautify, minify and validate JSON with helpful error messages.
4.3 (3 ratings)Text processing on your device
Formatting and parsing run in your browser. The JSON input is not uploaded by this tool.
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Clear instructions
Find steps, examples and limitations below.
Use online
Open the tool in a supported web browser.
Free to use
No sign-up required. Tool-specific limits may apply.
Reference resources
- JSON Syntax Guide
JSON types, syntax errors and safe serialization examples.
How to use the JSON Formatter & Validator
Beautify, minify and validate JSON with helpful error messages.
- 1 Paste JSON into JSON input. Valid input is formatted automatically; invalid input shows a parsing error below the editor.
- 2 Choose 2 spaces, 4 spaces or Tabs. Enable Sort keys if you want object properties sorted, including nested objects.
- 3 Click Beautify for readable output or Minify for compact JSON, then copy or download the result using the output controls.
Example and practical tips
Try {"name":"Ada","active":true,"roles":["editor"]}. Beautify adds indentation and line breaks; Minify removes that formatting. Neither mode translates property names or checks your application schema.
Sort JSON keys before comparing files
Enable Sort keys and use the same indentation for both inputs. Object keys are sorted recursively, while array order remains unchanged. This reduces differences caused by object key order, but it is not a canonical JSON serializer for digital signatures.
Syntax validity versus API requirements
Valid JSON can still be rejected by an API if required fields or data types are wrong. Formatting makes the structure readable; it does not verify an application-specific schema.
Common JSON errors
Use double quotes for names and strings, remove trailing commas and JavaScript comments, and check matching brackets. Inspect text near the parser’s reported error position.
Check numeric precision and duplicate keys
Very large integers may lose precision when parsed in JavaScript. Duplicate keys may be overwritten by a parser. Check data meaning as well as syntax before copying the result.
Frequently asked questions
Why is my JSON invalid?
JSON requires double-quoted property names and strings. Comments, trailing commas and single-quoted strings are not accepted. Review the reported error and fix the input before formatting.
Does formatting preserve every number exactly?
The formatter uses JavaScript JSON parsing. Integers outside the safe integer range can lose precision, and duplicate object keys keep only the last value. Represent large identifiers as strings and retain your original input.
Is my JSON sent to a server?
Formatting and validation run in your browser. The formatter does not submit the JSON input to a server.
Practical guides
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How to Format and Validate JSON
Format JSON for reading, fix common syntax errors and understand what validation can check. Includes a valid example and cautions about numeric precision.
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How to Use JSON Formatter & Validator
Format and validate JSON online with 2-space, 4-space or tab indentation. Sort object keys, minify JSON and copy the result for free.
Report an issue
Something broken or not quite right? Tell us and we will look into it.