JSON Formatter & Validator
Paste any JSON to pretty-print, minify or validate it. Get precise error location when the JSON is invalid.
About this tool
JSON Formatter & Validator takes messy or minified JSON and pretty-prints it with consistent indentation, so nested objects and arrays become easy to read. It also validates the JSON and points to the exact spot where the syntax breaks.
Developers reach for it constantly — to inspect an API response, tidy a config file, or minify JSON before embedding it in code. Everything runs client-side, which means even sensitive payloads like tokens or customer records stay in your browser.
How to use
- Paste your JSON into the input area.
- Click Format to pretty-print it with clean indentation.
- Use Minify to strip whitespace down to a single compact line.
- If the JSON is invalid, read the error message to find the line and position of the problem.
- Copy the formatted or minified result with one click.
Features
- Pretty-print with consistent, readable indentation.
- Minify to remove all unnecessary whitespace.
- Strict validation with precise error location.
- Syntax highlighting on the output for easy scanning.
- Handles deeply nested objects and large arrays.
- 100% client-side — your JSON is never sent to a server.
Frequently asked questions
Does my JSON get uploaded when I format it?
No. Parsing, formatting and validation all happen in your browser, so sensitive data such as API keys or personal records never leaves your device.
What does the error message tell me?
When the JSON is invalid, the tool reports what went wrong and where — such as an unexpected character, a missing comma, or an unterminated string — so you can jump straight to the broken spot.
What is the difference between format and minify?
Format adds indentation and line breaks to make the JSON human-readable, while minify removes all whitespace to produce the smallest possible string for transport or storage.
Why does the tool reject trailing commas or comments?
Standard JSON does not allow trailing commas or comments. If your source has them, remove them first — they are valid in JavaScript objects but not in strict JSON.