Expecting property name enclosed in double quotes
An object key is not a proper double-quoted string. The three causes: single-quoted keys ('name'), unquoted keys (name:), or a trailing comma that leaves the parser expecting another key before the }. Fix the key at the reported line and column.
What the error means
Inside a JSON object the parser reached a spot where it needs a property name, and a property name must be a string in double quotes. It found a single quote, a bare word, or a } after a comma instead.
The three causes
1. Single-quoted keys: 'name' is invalid — JSON keys use double quotes: "name".
2. Unquoted keys: age: must be "age":. JavaScript allows bare keys; JSON does not.
3. Trailing comma: a comma after the last pair (36,}) makes the parser expect another key and hit }. Remove it.
Fix it fast
Paste the object above and hit Repair — it double-quotes keys, converts single quotes, and strips trailing commas in one pass. This is the Python json.decoder wording; the JavaScript equivalent is "Unexpected token" on the same input.
FAQ
My JSON came from a JavaScript object literal — why does it fail?
JS object literals allow unquoted and single-quoted keys and trailing commas; strict JSON allows none of those. Quote every key with double quotes.
Is this the same as JSON5?
JSON5 permits unquoted keys and single quotes. If you need those, treat the file as JSON5 and convert it to strict JSON before a standard parser reads it.
Where exactly is the bad key?
The line and column in the message point at the character where a property name was expected — usually the quote or word just there, or the } after a trailing comma.