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Paste the complete JSON document you want to check for syntax errors.
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JSON Validator
Validate JSON syntax online and inspect the document root type, nesting depth, node count, object keys, arrays, objects and scalar values.
Validate standard JSON syntax Reject empty or malformed documents Report document root type Measure nesting depth and node count
Tips
Start with the example, then replace it with your complete source.
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INPUT JSON document to validate *
Paste the complete JSON document you want to check for syntax errors. Example: {
"name": "John",
"active": true
}
Reading file…
Validation result
About the tool
What JSON Validator does
JSON Validator checks whether a document is syntactically valid JSON. It parses the complete input and returns a validity result together with useful structural information: root type, nesting depth, total nodes, objects, arrays, object keys, scalar values and input size.
Syntax validation answers a specific question: can a standards-compliant JSON parser read this document? It does not confirm that required fields, value types or business rules match a particular API. For that, validate the document against a JSON Schema.
Common JSON mistakes include trailing commas, single quotes, comments, unquoted property names, invalid escape sequences and missing closing braces or brackets.
How to use
- Paste JSON. Use the complete payload rather than an isolated fragment.
- Validate. The parser checks the full document.
- Read the result. Valid JSON includes structural statistics that help confirm what was parsed.
- Fix syntax errors. Correct malformed punctuation, quoting, escapes or incomplete structure.
- Check schema separately. Syntax validity does not replace application-specific schema validation.
Built for the task
Why use JSON Validator?
Focused controls, predictable output, and a workflow designed around this exact transformation.
01
Strict JSON parsing
Checks standard JSON syntax instead of accepting JavaScript-only extensions.
02
Structural statistics
See root type, depth, nodes, objects, arrays, keys and scalar values.
03
Source remains editable
Correct the original JSON and run validation again immediately.
04
Syntax vs schema clarity
The result clearly separates JSON grammar from application-specific validation rules.
Useful answers
Questions about JSON Validator
Practical details about input, output, privacy, limits, and the best way to use this tool.
01 What does a JSON validator check?
It checks whether the input follows JSON grammar and can be parsed as a complete JSON value.
02 Does valid JSON mean my API payload is correct?
No. Syntax validity does not verify required properties, allowed values or application-specific types. Use JSON Schema validation for those rules.
03 Are trailing commas valid JSON?
No. A trailing comma after the final array item or object property is invalid JSON.
04 Can JSON use single quotes?
No. JSON strings and property names use double quotes.
05 Are comments allowed in JSON?
Standard JSON does not support comments. Some configuration formats accept JSON-like extensions, but they are not RFC 8259 JSON.
06 Can the root value be an array?
Yes. A JSON document can contain an object, array, string, number, boolean or null as its top-level value.
07 Why show depth and node counts?
They help confirm the structure that was actually parsed and can reveal unexpectedly deep or large payloads.
08 What is the difference between JSON Validator and JSON Schema Validator?
JSON Validator checks syntax. JSON Schema Validator checks a valid JSON instance against structural and semantic rules described by a schema.
Learn JSON
Read the complete JSON Guide
Learn JSON objects, arrays, value types, validation, formatting, parsing, API workflows, and common syntax errors.
- Objects, arrays, and values
- Validation and formatting
- API and parsing workflows
Read guide
Practical explanations and examples
JSON syntax validation
A validator parses the complete document according to JSON grammar. Valid input can be an object, array, string, number, boolean or null. The structural summary helps verify whether a large payload was parsed in the shape you expected.
Common invalid JSON
Trailing commas, single quotes, comments, unquoted keys, bad backslash escapes and missing delimiters are frequent causes of parser errors. JavaScript object notation can look similar to JSON while still containing syntax that JSON does not permit.
JSON syntax vs JSON Schema
A syntactically valid document can still be wrong for an API. If a payload must contain specific properties or value types, continue with JSON Schema Validator. If the complete JSON document defines an API contract, use OpenAPI Validator to check its version, paths, operations, and responses.
Format valid JSON
After syntax passes, use JSON Formatter to pretty-print or normalize the document. For large nested data, JSON Viewer and JSON Path Finder can make inspection easier.
JSON specification
Standard JSON syntax is described by RFC 8259.