JSON Formatter &
Syntax Validator Guide
Pretty-print messy, single-line JSON data into a clean structure. Detect syntax errors with exact line numbers instantly in your browser.
Open Tool NowHow to Use — Step by Step
Paste Raw JSON
Input your raw JSON string into the left text editor. To test features, click Load Sample to import a pre-structured mock JSON payload.
Review Syntax Warnings
The parser validates your input in real time. If the syntax contains errors (like missing commas or single quotes), the exact line number and parsing error description will appear in a warning banner.
Pretty Print or Minify
Click Pretty Print to apply clean 2-space indentation and syntax highlighting. Alternatively, select Minify JSON to remove all whitespace for compact database storage.
Copy Result & Inspect Stats
Click Copy Output to copy the modified JSON to your clipboard. Review the metrics panel below the textareas to check the file size, key counts, and maximum nesting depth.
💡 Common JSON Mistakes & Best Practices
- Quotes: Standard JSON strings and keys must use double quotes ("). Single quotes (') or omitted quotes will fail validation.
- Trailing Commas: Do not include a comma after the final key-value pair or array element.
- Privacy: Excellent for analyzing configuration parameters, database dumps, and API response logs because all parsing runs locally. Your data is never uploaded.