JSON Formatter
Validate structure and make JSON easier to inspect.
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Paste JSON to validate its syntax and produce a consistently indented view. Invalid input reports a parsing error rather than returning misleading formatted output.
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What does a JSON formatter do?
It parses JSON to check whether the syntax is valid, then prints valid data with consistent indentation for easier reading.
Formatting does not validate an application's schema, business rules, or the meaning of the data.
Format a JSON document
JSON Syntax, Formatting, and Validation
JSON is a text format for exchanging structured data. Its strict syntax requires double-quoted property names and strings, valid commas and brackets, and JSON values such as strings, numbers, booleans, arrays, objects, or null. A formatter can make valid JSON easier to inspect by adding indentation and line breaks; a parser can point out syntax errors that prevent the data from being read. This tool uses the browser's JSON parser, so it does not guess how to repair invalid input or check whether a document matches a particular API schema. Developers, analysts, and students can use it to inspect payloads and configuration, but should still validate required fields and application-specific constraints in the system that consumes the data.
Key Features
💡 Pro Tips
- →When the parser reports an error, inspect the nearby quote, comma, colon, and bracket pairs first.
- →Validate the formatted result against the expected schema or API contract when field types and required values matter.
Common Mistakes
Pasting JavaScript object syntax and expecting it to parse as JSON
JSON does not permit unquoted property names, single-quoted strings, comments, or trailing commas.
Assuming valid JSON means valid application data
Syntax parsing cannot determine whether required fields, allowed values, or relationships meet an application's rules.
Last updated: 2026-10-27
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Quick Facts
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Frequently Asked Questions
Does JSON allow comments or trailing commas?
Standard JSON does not allow comments or trailing commas. Those constructs cause a parse error.
Is pasted data transmitted?
No. Formatting is performed in the current browser tab. Treat shared devices and browser history appropriately.
Will the formatter repair invalid JSON automatically?
No. It reports a parsing error so you can correct the input; it does not guess how malformed data should be changed.
Does valid JSON mean the data will work with my API?
No. Parsing checks syntax only. The API may require particular fields, types, or values that need separate schema or application validation.