Escaping Double Quotes in JSON

JSON (JavaScript Object Notation) is a widely used data format for exchanging information. It relies heavily on the use of double quotes to delimit strings. But what happens when you need to include a double quote character within a JSON string? This tutorial explains how to correctly escape double quotes and other special characters within JSON strings.

The Need for Escaping

JSON parsers interpret double quotes as the delimiters of strings. If you try to include a literal double quote without escaping it, the parser will likely misinterpret the string, leading to errors. The same principle applies to backslashes; because the backslash is used as the escape character, it too needs to be escaped if you want to represent a literal backslash.

How to Escape Double Quotes

The solution is to escape the double quote character using a backslash (\). This tells the JSON parser to treat the following character as a literal character rather than a string delimiter.

Here’s how it works:

• Literal Double Quote: To represent a double quote character within a JSON string, use \".

Example:

Let’s say you want to create a JSON string that contains the phrase "He said, "Hello!"" Here’s how you would correctly format it in JSON:

{
  "message": "He said, \"Hello!\""
}

Notice how the double quotes within the string are escaped with backslashes. This tells the parser that those double quotes are part of the message, not string delimiters.

Escaping Backslashes

Since the backslash is the escape character, it also needs to be escaped if you want to represent a literal backslash within a JSON string. This means you need to use two backslashes (\\).

Example:

{
  "path": "C:\\Program Files\\MyApplication"
}

In this example, the backslashes in the file path are escaped so that they are interpreted as literal backslashes and not escape characters.

Understanding the Process

Consider this scenario: you’re building a JSON string within a programming language (like JavaScript or Python). The programming language also has its own rules for escaping characters within strings. This can lead to a double layer of escaping.

• Language Escaping: Your programming language might process escape sequences (like \n for a newline) before the JSON parser sees the string.
• JSON Escaping: The JSON parser then processes its own escape sequences.

To avoid confusion, it’s crucial to understand how both layers of escaping work.

Using Raw Strings (Recommended)

Many programming languages offer "raw strings" which can significantly simplify JSON string creation. Raw strings disable most escape sequence processing, allowing you to include literal backslashes and double quotes without needing to escape them multiple times.

• JavaScript: Use String.raw template literals:

const jsonString = String.raw`{"message": "He said, \"Hello!\""}`;
const obj = JSON.parse(jsonString);
console.log(obj);

• Python: Use the r prefix:

json_string = r'{"message": "He said, \"Hello!\""}'
import json
obj = json.loads(json_string)
print(obj)

In summary:

• Escape double quotes within JSON strings using a backslash (\").
• Escape backslashes using two backslashes (\\).
• Consider using raw strings in your programming language to simplify JSON string creation and avoid double escaping.