JSON Formatter & Validator — Format and Validate JSON Instantly

Beautify, validate, and minify JSON instantly. Syntax-highlighted with exact line-number error detection — runs entirely in your browser.

Error detection with exact line and column numbers — not just "invalid JSON".

Indent

Input

Press Cmd/Ctrl + Enter to format

Output

Paste JSON to begin.

How to Use

Paste your JSON — Copy raw or minified JSON from your API, config file, or clipboard and paste it into the input editor on the left.
Choose format options — Pick indent style (2-space, 4-space, or tab) to beautify, or click Minify to strip all whitespace into compact one-line JSON.
Copy or download — Click Copy to send the formatted JSON to your clipboard, or download it as a .json file. Use Cmd/Ctrl+Enter as a keyboard shortcut to format instantly.

Why Use This Tool

JSON is the universal format for API responses, configuration files, log payloads, and inter-service communication — but raw JSON is rarely human-friendly. A response from a REST endpoint or a stored config blob often arrives as one long minified line, with no way to scan its shape at a glance. Pretty-printing with consistent indentation turns it back into something you can actually read, debug, and edit.

Validation is the other half of the job. JavaScript's JSON.parse throws a generic SyntaxError when something is wrong, but most online formatters surface only the high-level message — leaving you to hunt through the file for the broken character. This tool surfaces the exact line and column of the error, so you can jump straight to the misplaced comma, missing brace, or unquoted key without re-reading the whole document.

And because every byte of processing happens inside your browser, you can paste sensitive data — internal API responses, database dumps, auth tokens, customer records — without it ever leaving your device. No uploads, no logging, no third-party services in the path.

Frequently Asked Questions

Paste your JSON into the editor and our validator checks it instantly. If valid, you'll see a green confirmation badge. If invalid, we show the exact line and column where the syntax error occurs, plus a human-readable cause like "Unexpected comma" or "Missing closing brace" — so you can jump straight to the broken line.

Formatting (pretty-printing) adds indentation and line breaks so humans can read and edit the structure easily. Minifying does the opposite — it removes every whitespace character to shrink file size, ideal for API payloads and cutting bandwidth costs. Both produce semantically identical JSON, just optimized for different audiences.

Yes. Our formatter processes JSON up to 1MB smoothly using chunked rendering with setTimeout so the browser stays responsive and never freezes. For very large datasets above 10MB we recommend splitting them into smaller files first, since browsers have memory limits regardless of how the formatter is built.

No. Everything runs entirely inside your browser using JavaScript. Your JSON never leaves your device, never touches our servers, and isn't logged or cached anywhere. That makes it safe for sensitive data like API responses, database dumps, secrets, and internal config files.