What are the rules of JSON syntax?

JSON has a small, strict set of syntax rules. Data is built from objects ({ }) and arrays ([ ]); keys must be double-quoted strings; and values can only be a string, number, true, false, null, object, or array.

{
  "id": 1042,
  "title": "Hello",
  "tags": ["a", "b"],
  "published": true,
  "meta": null
}

The rules

• Keys and string values use double quotes, not single quotes
• Separate key-value pairs and array items with commas, but no trailing comma after the last one
• Numbers are written plainly (42, 3.14, -1e5) with no quotes
• Use the literals true, false, and null (lowercase)
• Comments are not allowed in standard JSON

Not sure if your JSON is valid? Paste it into the JSON validator. It flags the exact line and reason for any error as you type. Learn more in fixing validation errors.