f1e2d3c4b5

f1e2d3c4b5 is a ten-character string consisting of digits and lowercase hexadecimal letters. In documentation and demonstrations, it is commonly used as an example identifier or surrogate key in software systems and data samples. Unlike a version control commit hash, it is not tied to any particular repository or standard.

Its format mirrors hexadecimal tokens used in computing, but it lacks a prefix such as 0x and is case sensitive. The term uses digits 0-9 and letters a-f, and the overall length is fixed at ten characters, making it easy to recognize in examples.

Typical uses include as a placeholder primary or foreign key in database schemas, a sample token in API requests, or a fragment of a hash shown for illustration. It may also appear in tutorials to demonstrate token handling, serialization, or input validation.

If generated at random, a ten-character hex string has 16^10 possible combinations, making accidental collisions unlikely in small datasets but not cryptographically secure. For security-sensitive identifiers, longer tokens with additional entropy are recommended.

As a nonstandard identifier, its meaning is entirely context-dependent. Users should rely on explicit documentation to assign significance to such strings in real systems. See also hexadecimal notation, tokenization, and surrogate keys.