{
  "id": 19899546,
  "title": "5 reasons your JSON fails to parse (and how to fix each one)",
  "url": "https://urgent.news/2026/11/14/5-reasons-your-json-fails-to-parse-and-how-to-fix-each-one",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-11-14T01:50:43.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/aztechtools/5-reasons-your-json-fails-to-parse-and-how-to-fix-each-one-54b6"
  },
  "original_language": "en",
  "account": "When a parser encounters an unexpected comma, the issue is usually one of five common mistakes. First, JSON does not permit a trailing comma after the last item, even though JavaScript allows it. For example, removing the final comma from `{ name : Ana , age : 30 }` resolves the error.\n\nSecond, keys and strings in JSON must be enclosed in double quotes. An object like `{ name : Ana }` is a valid JavaScript object, but it is not valid JSON syntax. Changing the quotes to double quotes makes it a proper JSON object.\n\nThird, keys in JSON cannot be unquoted. An object like `{name: Ana }` will fail to parse because every key requires double quotes. Fixing this by adding the missing quotes will typically resolve the parsing problem.\n\nFourth, JSON has no support for comments. Any `//` or `/* */` comments will cause parsing to fail. Before attempting to parse the data, remove any comments from the JSON string.\n\nFifth, invisible characters at the beginning of the file can sometimes cause problems. A Byte Order Mark (BOM) or a line number that was inadvertently pasted can interfere with the first token in the JSON data. If the error indicates position 0 and the file appears correct, inspect the data for these types of invisible characters. Use a formatter available online to pinpoint the exact location. Once identified, make the necessary correction and rerun the parsing.\n\nIf you are parsing data obtained from a log or a Python print statement, a thorough inspection and cleanup of quotes and trailing commas can save a significant amount of manual editing time. Two free tools are available to assist with this process. The Formatter at https://snipferry.com/json/formatter and the Repair tool at https://snipferry.com/json/repair both operate directly in your web browser, ensuring that your original data remains confidential.",
  "summary": "If a parser throws Unexpected token , the cause is almost always one of five things. 1. Trailing comma JSON does not allow a comma after the last item, even though JavaScript does. { \"name\" : \"Ana\" , \"age\" : 30 , } Remove the last comma. 2. Single quotes Keys and strings must use double quotes. {'name': 'Ana'} is a JavaScript object, not valid JSON. 3. Unquoted keys {name: \"Ana\"} fails. Every key…",
  "key_points": [
    "JSON disallows trailing commas after the last item",
    "Keys and strings in JSON must be enclosed in double quotes",
    "JSON has no support for comments, which cause parsing failures"
  ],
  "editors_take": "Strict adherence to specific syntax rules like double quoting and comment removal distinguishes JSON from JavaScript, requiring developers to prioritize precise formatting to avoid common parsing failures.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}