JSON Validator
The JSON Validator helps you check whether your JSON data follows valid JSON syntax. Identify common problems such as missing commas, incorrect quotation marks, misplaced brackets, and malformed values before using data in APIs or applications. This free online JSON validation tool makes troubleshooting easier for developers, students, and anyone working with structured data. Paste your JSON to check its validity and find syntax issues.
Use your own data or load a sample to see how this tool works.
Validation and processing errors are kept in this browser session so you can review the failure location and download a JSON log.
What is JSON Validator?
A JSON Validator checks whether your JSON data follows the correct JSON syntax and identifies formatting problems that can prevent it from being processed. Validate API payloads, configuration files, and structured data by checking for issues such as missing commas, invalid quotation marks, and mismatched brackets with this free online JSON validation tool.
Why use this tool?
- Catch syntax errors before an API or application rejects the payload.
- Separate JSON syntax problems from application-level schema validation.
- Use a quick browser tool when investigating copied API responses or configuration files.
How to use JSON Validator
- Step 1. Paste the complete JSON document into the input.
- Step 2. Run validation and read the reported error or success state.
- Step 3. Correct the syntax and validate again before using the document in your application.
Common use cases
Validate JSON before using an API payload
Parsing catches malformed JSON before the data reaches the next step in your application.
function isValidJson(text) {
try {
JSON.parse(text);
return true;
} catch {
return false;
}
}
console.log(isValidJson('{"active":true}')); // trueImportant notes
- Valid JSON is not necessarily valid for a particular API schema.
- Common mistakes include trailing commas, single-quoted strings and unquoted property names.
More JSON & Data Tools
JSON Validator FAQ
Does JSON validation check my API schema?
Basic JSON validation checks JSON syntax. API-specific rules require a schema or application-level validation.
Why is my JSON invalid?
Typical causes include missing commas, unmatched brackets, invalid quotes and trailing commas.