JSON Validator

Validate JSON and fix syntax errors

Paste JSON and see immediately whether it is valid. If it isn't, the error is shown under the editor, and Auto-fix can repair the most common mistakes for you.

Open the JSON validator → Free · No sign-up · Runs in your browser

How to use it

Paste or type JSON into the editor. It is checked automatically as you type.
A green Valid JSON status means the document parses correctly.
If there is an error, read the message in the status bar, or click Auto-fix to repair common problems, then Format.

Example

Invalid input

{name: “Ada”, roles: ["admin"]

After Auto-fix and Format

{
  "name": "Ada",
  "roles": [
    "admin"
  ]
}

Features

Validates as you type

No button to press. The status bar always shows whether the current document is valid.

Clear error messages

See what the parser could not read so you can fix it quickly.

Auto-fix

Replaces smart quotes, quotes bare keys, adds missing commas between objects and closes unclosed brackets.

Schema validation

Need more than syntax? Check the structure against a JSON Schema in the Schema tool.

Frequently asked questions

What does Auto-fix repair?

Curly “smart” quotes copied from documents, unquoted object keys, missing commas between adjacent objects or arrays, and missing closing } or ] brackets.

Why is my JSON invalid?

The most common causes are single quotes instead of double quotes, unquoted keys, trailing commas, comments, and missing brackets. JSON allows none of these.

Can I validate against a JSON Schema?

Yes. Use the Schema tool to generate or paste a schema and validate the editor JSON against it.

Is my data private?

Yes. Validation runs locally in your browser and nothing is uploaded.