A Unicode code point is a numeric value identifying a character or other encoded abstract element. Counting code points is more reliable than assuming every character occupies one byte. section 5.4.1 section 6.3.2
For storage limits, a conservative estimate treats each code point as four bytes by assuming UTF-32. Enforce maximum lengths explicitly and generally reject excessive input rather than silently truncating it. section 5.4.1
Visually identical text
The visible character “á” can use U+00E1 or the sequence U+0061 followed by U+0301. These representations look identical but produce different stored data, so unique web-API identifiers should generally use ASCII. section 6.3.2
