What's the difference between UTF-8 and UTF-8 without BOM?

Question

What\'s different between UTF-8 and UTF-8 without a BOM? Which is better?

Answer 1

The other excellent answers already answered that:

• There is no official difference between UTF-8 and BOM-ed UTF-8
• A BOM-ed UTF-8 string will start with the three following bytes. EF BB BF
• Those bytes, if present, must be ignored when extracting the string from the file/stream.

But, as additional information to this, the BOM for UTF-8 could be a good way to "smell" if a string was encoded in UTF-8... Or it could be a legitimate string in any other encoding...

For example, the data [EF BB BF 41 42 43] could either be:

• The legitimate ISO-8859-1 string "ABC"
• The legitimate UTF-8 string "ABC"

So while it can be cool to recognize the encoding of a file content by looking at the first bytes, you should not rely on this, as show by the example above

Encodings should be known, not divined.