NPANXXXXXX

NPANXXXXXX is a notional identifier pattern used in documentation and tutorials to illustrate string formats that combine a fixed prefix with a placeholder suffix. It is not a real-world standard and has no official meaning.

The pattern consists of a fixed prefix "NPAN" followed by six placeholder characters "XXXXXX." In practice, the X's denote positions where actual characters—typically numeric digits or alphanumeric codes—are to be substituted. The exact allowed characters and whether separators are used depend on the domain and the specific implementation.

Common usage includes demonstrating regular expressions, input validation, data modeling, and anonymized sample data. It helps explain constraints such as length, character set, and uniqueness without exposing real data. When seen in real data, NPANXXXXXX should be treated as a placeholder and replaced with legitimate values.