Validate JSON Online

Worked example

Example: API returns 400—validator shows a trailing comma on line 14 before you redeploy.

When to use this

• Debugging webhook payloads.
• Checking exported config before production.
• Learning JSON syntax in tutorials.

Common examples

• Trailing comma error on last object property.
• Single quotes rejected—use double quotes.
• Unescaped newline inside a string value.
• Large config file validates after removing comments (JSONC ≠ JSON).
• Empty input vs {} — empty is invalid; empty object is valid.

Common mistakes

• Trailing commas after last array/object item.
• Unescaped newlines inside strings.
• Using undefined or NaN (invalid in JSON).

How it works

Parses JSON with the browser JSON parser and reports syntax errors (and location hints when available). Validates structure only—not a schema/OpenAPI checker.

Limitations

Validates JSON syntax only. Schema, business rules, and duplicate keys are not checked unless noted.

Privacy and file handling

Your data stays on your device and is not uploaded.

Formula or method

JSON.parse on your device. Schema validation is out of scope; pair with a schema tool when you need type constraints.