How to Format, Minify and Validate JSON (and Fix Common Errors)

JSON is the language APIs, config files and web apps use to exchange data. When it arrives as one long line, it is impossible to read, and one missing comma can break an entire application. A formatter and validator fixes both problems.

How to use the JSON Formatter

1. Open the JSON Formatter and Validator.
2. Paste your JSON.
3. Choose format to make it readable with indentation, or minify to shrink it for production.
4. If something is wrong, the validator tells you where the error is.

Try it now: JSON Formatter and Validator is free, works in your browser and needs no signup.

The most common JSON errors

• Trailing commas: {"a": 1,} is invalid. Remove the last comma.
• Single quotes: JSON needs double quotes: "name", not 'name'.
• Unquoted keys: {name: "Ali"} is valid JavaScript but not valid JSON.
• Comments: standard JSON does not allow // or /* */ comments.
• Missing brackets: every { and [ needs a matching close.
• Special values: undefined and NaN are not valid JSON; use null.

Format vs minify

Formatted JSON is for humans: reading API responses, debugging and code reviews. Minified JSON removes spaces and line breaks to make files smaller for production and network transfer. The data is identical.

Is it safe to paste API data?

Your data is processed in your browser and is not sent to our server. Even so, it is good practice to remove live API keys and passwords before pasting data into any website.

Related developer tools

Need to encode a string? Try Base64 Encode and Decode.

Try it now: JSON Formatter and Validator is free, works in your browser and needs no signup.