{
  "id": "magic/utf16-bom-le",
  "family": "magic",
  "slug": "utf16-bom-le",
  "title": "UTF-16 LE BOM (FF FE)",
  "summary": "A UTF-16 little-endian byte-order mark is the 2-byte sequence 0xFF 0xFE — the LE serialization of U+FEFF. The reversed order 0xFE 0xFF signals UTF-16 big-endian. The BOM lets a decoder pick the byte order of the following UTF-16 text.",
  "kind": "signature",
  "aliases": [
    "UTF-16 BOM",
    "UTF-16LE BOM",
    "FF FE",
    "byte order mark"
  ],
  "status": "standard",
  "verification": "verified",
  "tier": "B",
  "source_url": "https://www.unicode.org/faq/utf_bom.html#bom4",
  "source_version": "Unicode FAQ UTF-8/BOM (FF FE = UTF-16LE, FE FF = UTF-16BE form of U+FEFF)",
  "retrieved_date": "2026-05-29",
  "see_also": [
    "magic/utf8-bom"
  ],
  "ext_type": "file-signature@1",
  "ext": {
    "magic_hex": "FF FE",
    "offset": 0,
    "magic_ascii": "\\xff\\xfe",
    "extensions": [
      "txt"
    ],
    "mime": "text/plain",
    "spec": "The Unicode Standard (U+FEFF byte order mark)",
    "notes": [
      "FF FE = UTF-16 little-endian BOM; FE FF = UTF-16 big-endian BOM.",
      "Both are the encoding of U+FEFF in the respective byte order.",
      "CAUTION: a UTF-32LE BOM is FF FE 00 00, which begins with the same two bytes as the UTF-16LE BOM — check the following bytes to disambiguate.",
      "Without a BOM, UTF-16 defaults to big-endian per the Unicode standard, though in practice little-endian is common on Windows."
    ]
  },
  "updated": "2026-05-29T00:00:00Z"
}