JSON Validator
Quickly check whether your JSON is valid. Get precise error locations and descriptions. Works entirely in your browser.
Why use a JSON Validator?
Invalid JSON silently breaks applications — APIs return 400 errors, config loaders crash, and data pipelines fail. A dedicated validator gives you an exact error location and message rather than a cryptic stack trace. Use this before committing JSON configs, sending API payloads, or importing data. Pair it with the JSON formatter to prettify after validation and JSON diff to compare versions. Part of the developer tools suite.
Instant feedback
Validation runs on every keystroke so you catch syntax errors the moment they appear, not after submitting.
Structural stats
See the root type (object, array, string), top-level key count, and total character count at a glance.
Client-side only
Your JSON data never leaves the browser — ideal for validating sensitive configs, credentials, or PII-containing payloads.
JSON data types & examples
JSON supports exactly six data types. Understanding them prevents type-coercion bugs in APIs and parsers.
| Type | Example value | Notes |
|---|---|---|
| String | "hello world" | Must use double quotes; escape special chars with \ |
| Number | 42 / 3.14 / -7 / 1e10 | No quotes; integers and floats; no hex or octal literals |
| Boolean | true / false | Lowercase only — True is invalid JSON |
| Null | null | Represents absence of value; undefined is not valid JSON |
| Object | {"key": "value"} | Unordered key-value pairs; keys must be double-quoted strings |
| Array | [1, "two", null] | Ordered list; can mix types; no trailing comma allowed |