JSON & Data· Updated 2026-08-30· 3 min read

JSON Escaping Explained: Quotes, Backslashes & Unicode Escapes

In JSON strings, certain characters have syntactic meaning or cannot be represented directly as raw bytes. RFC 8259 defines explicit two-character escape sequences prefixed by backslash (\).

The Windows File Path Bug

Writing file paths using single backslashes like "C:\Users\admin" will crash the parser. Because \U is not a valid escape sequence, JSON.parse() halts. Every backslash must be doubled as "\\".

Invalid (Unescaped backslashes)

{
  "directory": "C:\Program Files\Tools"
}

Valid JSON (Double backslash)

{
  "directory": "C:\\Program Files\\Tools"
}

Unicode Hex Escapes (\uXXXX)

Characters outside ASCII can be written either directly as UTF-8 characters or as 4-digit hexadecimal code units: \u00A9 for ©. Characters beyond the Basic Multilingual Plane (like emojis 🚀 U+1F680) require surrogate pairs in JSON: "\uD83D\uDE80".

Interactive Tool

Unicode Inspector

Inspect Character Code Points

Inspect code points, surrogate pairs, and UTF-8 byte lengths in Unicode Inspector.

Preset Payload

Hello \uD83D\uDE80 World