Top JSON Errors & How to Fix Them Quickly

JSON is simple—but small mistakes can break your entire API, UI component, or application. Here are the most common JSON errors developers run into and how to fix them in seconds.

1. Missing or Extra Commas

Error Example:

{
    "name": "Munzir"
    "role": "Developer"
}

Fix: Add a comma between key-value pairs.

{
    "name": "Munzir",
    "role": "Developer"
}

2. Using Single Quotes Instead of Double Quotes

Error Example:

{
    'name': 'Munzir',
    'active': true
}

Fix: JSON requires double quotes.

{
    "name": "Munzir",
    "active": true
}

3. Trailing Commas

Error Example:

{
    "name": "Munzir",
    "skills": ["Java", "MERN",],
}

Fix: Remove trailing commas.

{
    "name": "Munzir",
    "skills": ["Java", "MERN"]
}

4. Unescaped Characters

Error Example:

{
    "bio": "I love coding in "Java""
}

Fix: Escape quotes using \".

{
    "bio": "I love coding in \"Java\""
}

5. Keys Without Quotes

Error Example:

{
    name: "Munzir",
    role: "Developer"
}

Fix: Always wrap keys in quotes.

{
    "name": "Munzir",
    "role": "Developer"
}

6. Wrong Bracket or Brace

Error Example:

{
    "skills": ["Salesforce", "Java"
}

Fix: Close arrays and objects properly.

{
    "skills": ["Salesforce", "Java"]
}

7. Duplicate Keys

Error Example:

{
    "name": "Munzir",
    "name": "Nabeel"
}

Fix: Remove the duplicate and keep one key.

Conclusion

JSON errors are extremely common, but most of them are easy to fix once you know where to look. Using tools like JSON Junction's Formatter and Comparator can help you instantly identify and correct JSON issues.