Explainer
What is a Unicode code point?
A code point is a number assigned by Unicode. An emoji can be one code point, or a short sequence of them working together.
The U+ notation
Code points are written in hexadecimal with a U+ prefix. U+1F600 is one code point. The number identifies the character, not the font or the artwork.
Some emoji are sequences
Family, profession and flag emoji often combine several code points with a zero-width joiner (U+200D). The sequence is displayed as one glyph, but it is stored as multiple code points.
Variation selectors
U+FE0F asks a platform to use the emoji presentation instead of a text-style glyph. Some systems add or omit it automatically. This is why the same emoji can look like different byte sequences in different tools.
Encoding is a separate step
UTF-8 and UTF-16 are ways to store code points as bytes. The code point is the same; the byte sequence changes with the encoding. Databases and APIs should use UTF-8 end to end.