How to Validate JSON

Invalid JSON is one of the most common causes of API errors. Here are five ways to validate your JSON.

Method 1: Online Validator (Fastest)

The quickest way is to paste your JSON into JSONKit's validator. It highlights errors with exact line and column numbers and explains what went wrong in plain English. Validation runs live as you type — no button press needed.

Method 2: Browser Console

Open any browser's developer console (F12) and run:

javascript

JSON.parse('your json string here');

This returns the parsed object if valid and throws a SyntaxError if not.

Method 3: Node.js

javascript

const fs = require('fs');
try {
  const data = JSON.parse(fs.readFileSync('data.json', 'utf8'));
  console.log('Valid JSON:', data);
} catch (e) {
  console.error('Invalid JSON:', e.message);
}

Method 4: Python

python

with open('data.json') as f: try: data = json.load(f) print('Valid JSON') except json.JSONDecodeError as e: print(f'Invalid: {e}') ```

Method 5: JSON Schema Validation

JSON Schema lets you validate not just syntax but also the structure and types of your data:

json

{
  "type": "object",
  "required": ["name", "age"],
  "properties": {
    "name": { "type": "string" },
    "age":  { "type": "number", "minimum": 0 }
  }
}

JSONKit supports JSON Schema validation (draft-07 and 2020-12).

Common JSON Errors

Missing comma between properties
Trailing comma after the last property
Single quotes instead of double quotes
Unquoted keys — all keys must be strings
undefined — not a valid JSON value, use null instead

How to Validate JSON — 5 Methods Explained