JSON Formatter & Validator: Format, Minify and Fix JSON
JSON is the most common way apps and websites exchange data, but a single missing comma can break it. A JSON Formatter & Validator makes messy data readable and tells you exactly where something is wrong.
What is JSON?
JSON stands for JavaScript Object Notation. It stores information as simple pairs of names and values, such as {"name": "Lumara"}. APIs, settings files and databases use it because it is light and easy for both people and programs to read.
What does a JSON formatter do?
- Format (beautify): adds indentation and line breaks so nested data is easy to follow.
- Minify: removes extra spaces so the file is as small as possible.
- Validate: checks that the JSON follows the rules and reports the line and column of any error.
- Sort keys: puts properties in A to Z order, which makes files easier to compare.
How to use the tool
- Paste your JSON into the input box.
- Check the status bar. It shows a green "Valid JSON" or a red message explaining the problem.
- Choose Format or Minify, and pick 2 spaces, 4 spaces or tabs.
- If there is an error, press Jump to the error to go straight to it.
- Copy the result or download it as a .json file.
Common JSON mistakes
- Trailing commas: a comma after the last item is not allowed.
- Single quotes: JSON requires double quotes around names and text.
- Unquoted names: property names must be in double quotes.
- Comments: JSON does not support comments.
- Missing brackets: every { and [ needs a matching } and ].
Who uses a JSON validator?
Developers debug API responses with it, testers check data files, and analysts read exports from apps and databases. Anyone who receives a long, unreadable block of JSON can make sense of it in seconds.
Private and free
Your data stays in your browser. It is never uploaded or stored, which makes the tool safe for private API responses and test data. There is no sign up or login.
Frequently asked questions
Is there a size limit? There is no fixed limit, but very large files may be slow on older devices.
Why does my large number change? JavaScript can safely hold whole numbers only up to 9,007,199,254,740,991. Larger values can lose precision, as in any JavaScript tool. Keep them as text if exact digits matter.