JSON Validator
Validate, format, and fix your JSON online. Instant error detection with line numbers.
Frequently Asked Questions
- What is JSON?
- JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write, and easy for machines to parse and generate.
- How do I validate JSON?
- Paste your JSON into the editor above and click 'Validate'. The tool will check for syntax errors and show the exact line and column where the error occurs.
- What are common JSON errors?
- Common errors include: missing commas between items, trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and missing closing brackets.
- Is this tool free?
- Yes, DevChecker is completely free. Your JSON is processed entirely in your browser — nothing is sent to any server.
- Can I validate large JSON files?
- Yes, you can paste or drag-and-drop JSON files of any size. Processing happens in your browser.