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JSON Formatter, Validator & Beautifier Online

Developer Tool

Validate, format (beautify), and minify JSON online. Detects syntax errors with precise line numbers. Supports custom indentation (2 or 4 spaces). All processing is 100% client-side — your JSON data never leaves your browser.

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Next Step — Complete Your Workflow

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Encode JSON to Base64 →

Encode the formatted JSON for use in API headers or storage

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URL-encode JSON →

Encode JSON for use as a URL query parameter

How to use JSON Formatter, Validator & Beautifier Online

1Enter your values in the fields above.
2Results calculate instantly as you type — no button click needed for most tools.
3Copy the result using the Copy button.
4Use the Next Step workflow to chain into related tools.
5All processing runs locally in your browser. No data is transmitted.

Frequently Asked Questions

Why is my JSON invalid?

Common JSON errors: trailing commas after last key/value (not allowed in JSON), using single quotes instead of double quotes, unescaped special characters in strings, or comments (JSON doesn't support comments).

What is the difference between JSON and JSONC?

JSON (JavaScript Object Notation) does not support comments. JSONC (JSON with Comments) is a superset used by VS Code for config files. Our validator is strict JSON — use a JSONC validator for config files with comments.