Random strings for testing and identifiers
Random strings turn up constantly in development: seeding a test database, filling a form to check field validation, generating coupon codes, or producing sample data of a particular shape. This generator produces them in bulk, from whatever alphabet you specify.
The randomness is cryptographic. That matters less for test fixtures than for passwords, but there is no reason to use a weaker source, and it means these strings, at a sensible length, are suitable for values that need to be unguessable — invite codes, temporary tokens, one-time links.
Choosing an alphabet
Longer alphabets pack more entropy into fewer characters, but they are harder to read aloud or type. For anything a person will handle, dropping the ambiguous pairs — 0 and O, 1 and l and I — costs a fraction of a bit per character and eliminates a whole category of support ticket. Use the custom field for that: 23456789ABCDEFGHJKMNPQRSTUVWXYZ is a common choice.
For standard identifiers use the UUID generator. For readable placeholder prose use the Lorem Ipsum generator.