JSON Validator
Check JSON syntax and find parser errors in your browser.
Validation Result
Find JSON syntax errors
Enter JSON and select Validate JSON. Your browser's JSON parser checks the syntax and displays a line and column when the parser supplies a position.
Syntax is not the same as data validity
This tool uses your browser's JSON.parse to check up to 1,000,000 characters of JSON grammar. For example, {"age":"unknown"} is valid JSON even if an application expects age to be a number. Required fields, types, and API contracts need separate JSON Schema or application checks.
Use the reported error location
A trailing comma, single quote, missing comma, or unmatched bracket is a syntax error. When the browser parser supplies a position, the tool shows a line, column, source line, and ^ marker. Otherwise it says that the location is unavailable and shows the parser message. Check the token before the reported position too: the parser may notice an earlier mistake at the next character.
When to switch to the formatter
Use this page to locate a syntax problem. Once the JSON is valid, JSON Formatter can reprint it with two- or four-space indentation. The validator does not rewrite your input.
Standard reference
Frequently Asked Questions
Is my JSON sent to a server?
No. Syntax checking runs in your browser, and the input is not saved on a server or in a database. After a successful check, only a Tool-run statistics request is sent, without your input.
Does valid syntax mean my JSON Schema is valid?
No. This tool checks JSON grammar only. It does not validate required fields, value types, or other data rules.