JSON Formatter, Validator & Minifier
Format messy JSON into readable, indented code. Validate for errors and minify for production. The fastest way to work with JSON online.
How to Format JSON Online
- 1Paste your raw or minified JSON into the input area
- 2Click 'Format' to beautify, or 'Minify' to compress
- 3Errors are highlighted with a clear message if JSON is invalid
- 4Copy the formatted JSON with one click
Key Benefits
- Instant validation with detailed error messages
- Choose between 2-space, 4-space, or tab indentation
- Minify JSON to reduce file size for production
- Syntax highlighting for easy reading
Frequently Asked Questions
What is JSON formatting and why does it matter?
JSON (JavaScript Object Notation) is the most common format for exchanging data between APIs, apps, and config files. When data is minified or logged as a single line it becomes nearly impossible to read. Formatting adds indentation and line breaks so you can immediately see the structure, spot missing fields, and debug problems. It is a daily tool for anyone working with REST APIs, Node.js, or any configuration-heavy stack.
Why does my JSON show as invalid?
The most common culprits: trailing commas after the last item (valid in JavaScript but not JSON), keys without double quotes, single quotes instead of double quotes, unclosed brackets or braces, or control characters copied from a terminal. The error message shows the line and column where the parser gave up — start there.
Is my JSON data sent to a server?
No. All JSON processing happens entirely in your browser using JavaScript. Your data never leaves your device — safe for API keys, internal configs, or any sensitive payloads.
When should I use minified vs formatted JSON?
Use formatted JSON during development — it is far easier to read and diff. Switch to minified JSON for production API responses and bundled config files where every byte matters. Minifying a typical API response removes 15–30% of its size, which adds up at scale.
What are the most common use cases for a JSON formatter?
Inspecting REST or GraphQL API responses, editing package.json or tsconfig.json, reading structured log output, validating webhook payloads before deploying, and sharing data samples with teammates in a readable form.
Can I format JSON that contains comments?
Standard JSON does not allow comments — the spec is strict on this point. Files like tsconfig.json or VS Code settings.json that do include comments are technically JSONC (JSON with Comments), not pure JSON. Strip the comments before pasting here, or use a JSONC-aware editor like VS Code.