The error “Expecting property name enclosed in double quotes” is one of the most common JSON parsing failures developers encounter when working with APIs, configuration files, logs, or data exchange formats. In simple terms, the parser was looking for something like "name" and instead found a missing quote, a single quote, an unquoted word, or some other invalid character. It usually appears when a program tries to read JSON text but finds a character where the parser expected a quoted property name. Understanding this error is essential for anyone who builds web applications, mobile apps, backend services, data pipelines, or even simple scripts that consume JSON That's the part that actually makes a difference. But it adds up..
What the Error Means
JSON, or JavaScript Object Notation, is a lightweight text format used to store and transmit structured data. It is based on two main structures:
- Objects, which contain key-value pairs
- Arrays, which contain ordered lists of values
In a JSON object, every property name must be a string, and every string must be enclosed in double quotes. For example:
{
"username": "alice",
"age": 30,
"active": true
}
In this example, "username", "age", and "active" are property names. They are all enclosed in double quotes, as required by the JSON specification.
When a parser encounters something like this:
{
username: "alice",
age: 30
}
it may report an error such as “Expecting property name enclosed in double quotes” because username is not a valid JSON property name. The parser expected a quoted string but found an unquoted identifier instead Small thing, real impact. That alone is useful..
Why This Error Happens
This error is not always caused by a single obvious mistake. Worth adding: it can appear in many different situations, especially when data is generated dynamically, copied from another source, or transformed by multiple systems. Below are the most common causes.
1. Missing Double Quotes Around a Property Name
The most direct cause is a property name without double quotes. JSON does not allow bare property names.
Invalid:
{
name: "John"
}
Valid:
{
"name": "John"
}
This mistake is common when developers write JSON by hand or when a template engine accidentally omits quotes.
2. Using Single Quotes Instead of Double Quotes
Many programming languages allow single-quoted strings, but JSON does not. A property name written with single quotes will cause a parsing error Small thing, real impact..
Invalid:
{
'status': 'active'
}
Valid:
{
"status": "active"
}
This is especially common among developers who are used to JavaScript, Python, or SQL syntax, where single quotes may be acceptable in other contexts.
3. Trailing Commas
JSON does not allow trailing commas at the end of objects or arrays. A trailing comma can confuse the parser and cause it to expect another property name where none exists Less friction, more output..
Invalid:
{
"id": 1,
"name": "test",
}
Valid:
{
"id": 1,
"name": "test"
}
The comma after "test" makes the parser think another property will follow, but it reaches the closing brace instead That's the whole idea..
4. Unquoted Values That Should Be Strings
Although the error specifically mentions property names, related issues can appear nearby. Here's one way to look at it: a value that should be a string may be missing quotes.
Invalid:
{
"email": john@example.com
}
Valid:
{
"email": "john@example.com"
}
In some cases, the parser may report the error at the next property name because it has lost synchronization after the invalid value.
5. Improper Escaping of Special Characters
Double quotes inside a string must be escaped with a backslash. If they are not escaped, the parser may think the string has ended early.
Invalid:
{
"message": "He said "hello""
}
Valid:
{
"message": "He said \"hello\""
}
This can cause the parser to misinterpret the structure and eventually expect a property name where it finds something else The details matter here. Took long enough..
6. Hidden Characters or Encoding Problems
Sometimes the JSON text looks correct in a text editor, but hidden characters cause the parser to fail. These can include:
- Byte Order Mark (BOM)
- Non-breaking spaces
- Invisible Unicode characters
- Mixed line endings
- Corrupted encoding
A file that appears valid visually may still fail because the parser sees characters that are not part of the expected JSON structure.
7. Data Is Not Actually JSON
Not every response that looks like
