JSON Validator
Validate a JSON document and report syntax errors with location details when available.
Complete guide to JSON Validator
Tool Overview
The JSON Validator checks whether a block of text follows valid JSON syntax. It identifies structural problems such as missing commas, unmatched brackets or braces, invalid quotation marks, trailing commas, malformed values, or keys that are not properly quoted.
Because JSON is strict, a small syntax mistake can prevent an API request, configuration file, structured-data block, or application from being parsed. A validator provides a quick way to confirm correctness before the data is used elsewhere.
Why Validate JSON?
Developers frequently copy JSON between APIs, documentation, code editors, browser tools, and configuration files. During manual edits, it is easy to remove a comma, add an extra quote, or close the wrong bracket. Validation catches these issues before they become runtime errors.
The tool validates syntax, not the business meaning of the data. A JSON document can be syntactically valid while still containing the wrong field names, invalid product prices, missing required API values, or an inappropriate Schema.org structure. Schema validation is a separate step when a specific data model must be enforced. This distinction prevents a green syntax result from being mistaken for complete application-level validation.
Use Cases
- Check an API request body before sending it.
- Validate a JSON configuration file.
- Find syntax problems in copied JSON-LD.
- Verify generated JSON before storing it.
- Troubleshoot parsing errors in an application.
- Confirm that a minified JSON string is structurally valid.
Frequently asked questions
What makes JSON invalid?
Common causes include single quotes instead of double quotes, missing commas, trailing commas, unquoted keys, unmatched braces, and invalid escape sequences.
Does valid JSON mean the data is correct?
No. Syntax validation confirms that the text can be parsed as JSON. It does not verify whether the values are logically correct for your application.
Are trailing commas allowed in JSON?
No. Standard JSON does not allow a comma after the final item in an object or array.
Can JSON use single quotes?
Standard JSON requires double quotes for property names and string values.
What is the difference between a JSON formatter and validator?
A formatter improves readability by adding indentation. A validator checks whether the syntax is valid. Many tools provide both functions together.