{
  "id": "magic/utf8-bom",
  "family": "magic",
  "slug": "utf8-bom",
  "title": "UTF-8 BOM (EF BB BF)",
  "summary": "A UTF-8 byte-order mark is the 3-byte sequence 0xEF 0xBB 0xBF — the UTF-8 encoding of U+FEFF. It carries no endianness for UTF-8; it serves only as a signature that the following text is UTF-8. Unicode does not recommend its use and many tools treat it as optional/undesirable.",
  "kind": "signature",
  "aliases": [
    "UTF-8 BOM",
    "U+FEFF",
    "EF BB BF",
    "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 (EF BB BF = UTF-8 form of U+FEFF)",
  "retrieved_date": "2026-05-29",
  "see_also": [
    "magic/utf16-bom-le"
  ],
  "ext_type": "file-signature@1",
  "ext": {
    "magic_hex": "EF BB BF",
    "offset": 0,
    "magic_ascii": "\\xef\\xbb\\xbf",
    "extensions": [
      "txt"
    ],
    "mime": "text/plain",
    "spec": "The Unicode Standard (U+FEFF byte order mark)",
    "notes": [
      "EF BB BF is the UTF-8 serialization of the code point U+FEFF (ZERO WIDTH NO-BREAK SPACE used as BOM).",
      "UTF-8 has no byte-order ambiguity, so this is purely a format signature, not an endianness marker.",
      "Unicode neither requires nor recommends a UTF-8 BOM; it can break shebang lines, JSON parsers, and shell scripts if present.",
      "Detect it before decoding; many parsers strip a leading EF BB BF."
    ]
  },
  "updated": "2026-05-29T00:00:00Z"
}