What Is a JSON Validator?
A JSON validator checks whether your JSON (JavaScript Object Notation) data conforms to the correct syntax. It parses the input and identifies structural errors such as missing commas, unmatched brackets, or invalid data types, helping developers debug API responses and configuration files.
How to Use This JSON Validator
- Paste your JSON data into the input text area.
- Click the “Validate” button to validate.
- If the JSON is valid, a success message is shown. If invalid, the specific error and its location are displayed.
- Fix the reported issues and re-validate as needed.
Key Concepts
JSON supports six data types: strings (double-quoted), numbers, booleans (true/false), null, arrays, and objects. Common syntax mistakes include trailing commas after the last element, single quotes instead of double quotes, and unescaped special characters within strings. Valid JSON must have a single root element—either an object {} or an array [].
Frequently Asked Questions
What is the difference between JSON validation and JSON formatting?
Validation checks whether JSON syntax is correct and reports errors. Formatting (or pretty-printing) restructures valid JSON with proper indentation for readability without changing the data.
Can JSON contain comments?
Standard JSON does not support comments. If you need comments, consider using JSON5 or JSONC formats, which extend the specification to allow single-line and multi-line comments.
Why does my API response fail validation?
Common causes include trailing commas, single-quoted strings, unescaped control characters, or the response containing non-JSON content like HTML error pages.