Developer tools

JSON Formatter

Format, minify, and validate JSON online without uploading it. Get readable indentation, compact output, and clear syntax feedback directly in your browser.

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Your JSON stays in your browser. Formatting, minification, validation, and copying happen locally, so the JSON content is not sent to TheToolSite.

How to Use the JSON Formatter

  1. Paste JSON into the input box.
  2. Choose Format JSON for readable indentation or Minify JSON for compact output.
  3. If validation succeeds, review or copy the result.
  4. If an error appears, correct the nearby syntax and try again.

How JSON Formatting and Validation Work

The tool parses the JSON text into its data structure. If parsing succeeds, it serializes the same values with consistent two-space indentation or no extra whitespace. Formatting changes presentation, not the strings, numbers, booleans, null values, arrays, or objects represented by valid JSON.

JSON requires double quotes around property names and strings. It does not allow comments, trailing commas, single-quoted strings, NaN, Infinity, undefined, or unescaped control characters.

JSON Formatter Example

Compact input

{"name":"Ada","active":true,"skills":["math","code"]}

Readable output

The formatter places each property and array item on an indented line while preserving the same data. Minify removes those optional spaces and line breaks again.

Common JSON Errors

Typical errors include a missing comma between properties, a trailing comma before a closing brace, an unquoted property name, a single quote instead of a double quote, or a missing closing bracket. The reported location is a starting point; the actual mistake may appear immediately before it.

JSON Formatter Security

Local processing reduces unnecessary data transfer, but copied output and screenshots can still expose secrets. Redact access tokens, personal data, private URLs, and production credentials before sharing JSON with another person or service.

Community discussion

Comments

Share feedback about the tool. Don’t include private calculation inputs or account details.

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Method, sources, and review

Built and maintained by
TheToolSite AutomationAutomation
Method reviewed by
Derrick Frye
Last reviewed
August 19, 2026
Publisher
TheToolSite

Methodology

Parses the input with the browser JSON parser and serializes valid values with consistent indentation.

Assumptions

Limitations

Formatting cannot validate an application-specific schema or business rules. Duplicate object names may be collapsed by the parser, and number precision is limited by JavaScript numeric representation.

Rounding and precision

Whitespace is normalized by serialization. Numeric values use the browser JSON implementation; no independent decimal rounding is added.

Sources

Report a problem with this result or source

Common JSON Formatting Questions

What is the difference between formatting and minifying JSON?

Formatting adds indentation and line breaks for readability. Minifying removes optional whitespace for compact storage or transfer. Both represent the same valid JSON values.

Why is my JSON invalid?

Common causes include trailing commas, single quotes, missing commas, unquoted property names, comments, or unmatched braces and brackets. JSON is stricter than a JavaScript object literal.

Does this JSON formatter validate against JSON Schema?

No. It validates JSON syntax by parsing the text. It does not check required properties, data types, or business rules from a JSON Schema.

Is my JSON sent to a server?

No. Parsing, formatting, and minification happen locally in your browser.

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