Check JSON Online

Worked example

Example: validate a config snippet copied from Slack—trailing commas often fail before deployment.

When to use this

• You are debugging an API response or token claim.
• You need readable JSON or XML in a code review.
• You want a quick encode/decode without terminal tools.

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

• Pasting production credentials into shared browsers.
• Assuming decoded JWTs are verified—decode is not signature validation.
• Formatting invalid JSON without running the validator next.

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.