JSON Validator & Formatter — Check and Prettify JSON Instantly
JSON (JavaScript Object Notation) is the universal data interchange format used by virtually every web API, configuration file, and modern application. A single misplaced comma, unclosed bracket, or unquoted key causes the entire document to become unparseable — and tracking down that error by eye in a large blob of minified JSON is painful.
Our JSON Validator parses your input instantly and reports the exact line number and column where the syntax breaks. No more counting braces manually or squinting at a wall of text. The error message tells you precisely where the problem is so you can fix it in seconds.
The JSON Formatter takes valid JSON and outputs a clean, human-readable version with consistent indentation. Choose from 2 spaces (the most common convention for web projects), 4 spaces (popular in Python and Java communities), or a tab character (preferred in some style guides). The formatted output is fully copyable with a single click.
Both features run entirely in your browser. Your JSON data is never sent to any server — whether it contains API keys, personal data, database records, or proprietary configuration, it stays completely private. No account is needed, no rate limits apply, and results are instant regardless of document size.
Common uses include: validating API responses before parsing them in code, debugging configuration files that refuse to load, prettifying minified JSON for readability, checking JSON payloads in Postman or curl responses, formatting JSON before committing it to version control, and exploring the structure of unfamiliar data.
How to use the JSON Validator & Formatter
- Select the "Validate" tab to check JSON for errors, or "Format / Prettify" to reformat it.
- Paste your raw JSON into the input box.
- In Validate mode: any errors are shown instantly with line and column numbers.
- In Format mode: choose your preferred indentation (2 spaces, 4 spaces, or Tab), then click "Format JSON".
- Copy the formatted output with the Copy button.