JSON Validator Online - Check JSON Syntax
Validate JSON data instantly. Check syntax errors, missing commas, invalid quotes, trailing commas, and malformed JSON with clear error messages.
Find JSON Parse Errors Before They Break Your App
This JSON syntax checker is designed for pasted API responses, config files, package snippets, webhook samples, and database payloads. It helps identify common parsing failures such as unexpected tokens, missing commas, unclosed brackets, trailing commas, and unescaped quotes before you save or deploy the data.
Common JSON Syntax Errors Locator Checklist
If your database parser crashes, it's typically due to minor syntax oversights. Our online JSON validator with line numbers is built to flag these violations instantly:
| Syntax Error Type | Code Snippet Example | How to Fix the JSON Token |
|---|---|---|
| Trailing Comma Error | {"id": 1, "name": "Ninja",} | Remove the final comma after the last property value inside objects or arrays. |
| Missing Property Comma | {"id": 1 "name": "Ninja"} | Ensure every key-value structural pair is separated by a clear literal comma. |
| Unescaped Quotations | {"msg": "Click "Here""} | Use our JSON escape online tool to convert nested quotes into \". |
| Single Quotes Violation | {'id': '1024'} | ECMA-404 strictly mandates standard double quotes (") for all object properties and strings. |
| Mismatched Brackets | {"data": [1, 2, 3} | Check closure matching. Square brackets [] are for arrays, curly braces {} are for objects. |
Live JSON Syntax Checker Examples
Click below to see how our debugger captures mistakes and highlights line locations in real-time.
Example 1: Catching Missing Commas
In this example, there is no comma separating the second and third parameters. The engine flags this as a JSON parse error unexpected token block.
"secure_endpoint": true
"rate_limit_rpm": 120,Invalid JSON: Expected ',' or '}' after property value at Line 4Example 2: Trailing Comma Violation
While JavaScript allows trailing commas in objects and arrays, standard JSON files forbid them completely. Clicking above highlights the trailing error on line 4.
"node_west",
]Syntax Error: Unexpected token ']' at position 53 (Line 4)Frequently Asked Questions
How do I check JSON syntax errors online?
Paste your JSON into the validator and it will parse the document locally. If the JSON is invalid, the tool reports the error message and highlights the area that needs attention.
How do I validate JSON online?
Paste your JSON data into the input editor and it will be automatically validated. If there are syntax errors, the tool will highlight the problematic line and display a detailed error message explaining what went wrong. Valid JSON will show a success status with a summary of the data.
What are common JSON syntax errors?
Common JSON syntax errors include: using single quotes instead of double quotes for strings, trailing commas after the last item in an array or object, missing commas between items, unmatched brackets or braces, and unescaped special characters in string values.
Does this validator check JSON schema or just syntax?
This validator checks JSON syntax compliance with the RFC 8259 specification. It verifies that your JSON is structurally valid and can be parsed correctly by any standard JSON parser. It does not validate against a specific JSON Schema definition.
How do I find the exact location of a JSON error?
When a JSON error is detected, our tool highlights the problematic line in the editor with a red background and gutter marker. The status bar also shows the error position and a description of what caused the error, making it easy to locate and fix the issue.