Free JSON Formatter, Validator & Beautifier Online

The Free JSON Formatter That Does More Than Pretty-Print

Every developer has been there: a minified JSON blob from an API, a config file someone accidentally compacted, a log output so dense it is impossible to read. Our free online JSON formatter instantly transforms any JSON into clean, readable, syntax-highlighted code. But it goes much further than basic pretty-printing: validate, minify, sort keys alphabetically, explore with a collapsible tree view, and auto-repair broken JSON: all in one tool, all running locally in your browser. Your JSON data is never sent to our servers. All processing happens in JavaScript on your device. We log nothing. Free forever with no account required.

Four Core Actions

Beautify (Pretty-Print)

Format compact or minified JSON into readable, indented code. Choose your preferred indent style:

• 2 spaces: the most widely used convention, default in most code formatters
• 4 spaces: preferred in some languages and style guides
• Tab: uses actual tab characters, common in certain editor configurations
• Compact: no indentation but with space after colons and commas for minimal readable formatting

Minify

Strip all whitespace and produce the most compact valid JSON string. Ideal for reducing payload size before sending data over a network, embedding JSON in a script, or storing in a size-sensitive environment. The output is JSON.stringify(value) with zero spacing: the smallest possible valid representation.

Validate

Check whether your JSON is syntactically valid. The validator parses the JSON and reports the exact line number and column of the first error, with a plain-English explanation of what went wrong:"Unexpected token } at line 12, column 3: did you leave a trailing comma?" This pinpoints problems instantly without forcing you to count characters manually.

Sort Keys

Alphabetically sort all object keys at every level of nesting using localeCompare. Consistent key ordering makes JSON easier to diff, compare, and read: especially for large configuration objects and API response schemas with dozens of keys.

Auto-Repair: Fix Broken JSON Automatically

Real-world JSON is often imperfect. Copied from a JavaScript file, pasted from a comment, exported by a non-standard tool: broken JSON comes in many forms. The auto-repair engine fixes the most common issues automatically:

• Trailing commas:[1, 2, 3,] → [1, 2, 3]
• Single-quoted strings:{'key': 'value'} → {"key": "value"}
• Smart quotes: curly/typographic quote marks replaced with standard double quotes
• Unquoted object keys:{key: "value"} → {"key": "value"}
• JavaScript-style comments:// line comment and /* block comment */ stripped before parsing
• Python/JavaScript literals:True/False/None/NaN/undefined converted to their valid JSON equivalents

Repair runs only on text outside of string values: it never corrupts valid string content that happens to contain these patterns.

Collapsible Tree View

Switch from Code view to Tree view to explore your JSON as an interactive collapsible tree. Expand and collapse individual objects and arrays to navigate complex nested structures without scrolling through hundreds of lines. Use Expand All and Collapse All to jump between fully expanded and fully collapsed states instantly. Tree view is built lazily: it only renders when you open it, so the tool stays fast even with large JSON inputs.

Live Statistics

After beautifying or validating, the status bar shows live stats about your JSON:

• Size: file size in B, KB, or MB
• Lines: total line count of the formatted output
• Keys: total number of object keys across the entire structure
• Depth: maximum nesting depth reached in the structure

Input Methods

• Paste: type or paste JSON directly into the textarea
• Paste from clipboard: one-click paste button reads from your clipboard
• Upload file: select a .json or .txt file from your device (processed locally, no upload)
• Drag and drop: drop a JSON file anywhere on the tool
• Sample JSON: load a built-in example to explore the tool's features

Who Uses a JSON Formatter?

• Backend developers: format API responses and debug JSON payloads during development
• Frontend developers: inspect fetch/axios responses, format config files, validate JSON schemas
• QA engineers: compare API response structures, validate test fixtures
• DevOps engineers: format Terraform state files, Kubernetes manifests, and CI/CD config
• Data engineers: inspect and validate JSON data exports before importing into pipelines
• Technical writers: format JSON examples in documentation so they are readable

Free, Private & No Limits

Every feature of this JSON formatter is completely free: beautify, minify, validate, sort, repair, tree view, and download. No account needed, no usage limits, and no data ever sent to our servers. Paste, format, and go.