JSON Formatter + Tree Viewer

Paste JSON to pretty-print, minify, or validate it with syntax highlighting and an interactive tree view. Real time error detection with line numbers.

100% client-side. Your data never leaves your browser.

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Converters & Examples

Format a JSON API Response: Pretty Print Example

Pretty-print a minified JSON API response with proper indentation. Covers indent conventions, jq usage, minification trade-offs, and common syntax mistakes.

 Minify JSON Online: Compact JSON Tool

Remove whitespace from JSON to reduce file size. One-click minification for API payloads, config files, and log entries.

 Validate JSON Syntax: Online JSON Validator

Paste JSON and instantly see if it parses. Common syntax errors caught: trailing commas, single quotes, unquoted keys, missing brackets.

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JSON Formatter and Validator Online

JSON (JavaScript Object Notation) is the standard data format for APIs, config files, and data exchange. Paste minified or messy JSON here to format it with proper indentation, validate the syntax, or explore nested structures in the tree view. Catches trailing commas, missing brackets, and unquoted keys as you type.

How to Use

  1. Paste JSON into the input editor on the left
  2. Format or Minify using the buttons in the toolbar
  3. View the output as formatted text or switch to Tree view
  4. Adjust indentation with the dropdown (2 spaces, 4 spaces, or tabs)
  5. Copy the formatted result with one click

Features

Syntax Highlighting

The editor provides full JSON syntax highlighting powered by CodeMirror 6, with bracket matching, line numbers, and active line highlighting. The dark theme is designed for comfortable reading.

Real Time Validation

JSON is validated as you type. Errors are shown with descriptive messages and position information, so you can quickly find and fix issues like missing commas, unclosed brackets, or invalid values.

Tree View

The interactive tree view lets you expand and collapse objects and arrays to explore deeply nested structures. Values are color coded by type: strings in green, numbers in blue, booleans in orange, and null in gray.

Minification

The minify function removes all whitespace from valid JSON, producing the most compact representation. This is useful when you need to reduce payload size for API requests or storage.

Decoded a JWT and want to inspect the payload? The JWT Decoder extracts the JSON, and you can paste it here to format or explore the claims in the tree view. If you need to send JSON as a query parameter, run the minified output through the URL Encoder first.