JSON Formatter & Validator
Paste JSON below to automatically format it. Any syntax error is shown with a clear message. Need to count characters in text instead? Try the Character Counter.
🔒 Runs in your browser · Your data is never sent to a server
Notes
- JSON does not allow trailing commas, single quotes or comments. Including any of them causes a syntax error.
- Integers beyond JavaScript's numeric precision (about 15 to 17 digits) may be rounded when formatted. Store long IDs as strings.
- Your JSON is processed in the browser and is never sent to a server.
Glossary
JSON
Short for JavaScript Object Notation, a text format for representing data as key-value pairs. It is widely used for APIs and configuration files.
Syntax error
An error that occurs when JSON's rules (matching brackets, commas, quotes, etc.) are violated. It's usually caused by a missing closing bracket or a trailing comma.
FAQ
How do I find JSON syntax errors?
When the input is invalid, an error message is shown. Common causes are trailing commas, single quotes, unquoted keys, and comments, none of which are allowed in JSON.
What is the difference between formatting and minifying?
Formatting adds indentation and line breaks for readability; minifying removes whitespace to reduce size. The data normally does not change.
Are very large numbers handled exactly?
Integers beyond JavaScript's numeric precision (about 15 to 17 digits) may be rounded when formatted. For long IDs, store them as strings.
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