Random Token Generator produces unpredictable strings from the browser's cryptographic random source: hex, standard Base64, URL-safe Base64, a version 4 UUID, or a string built from a named or custom alphabet.
Custom-alphabet tokens are rejection-sampled so every character is equally likely. Nothing is sent anywhere.
It uses crypto.getRandomValues, the same source browsers use for cryptographic keys. It is suitable for API keys, session identifiers, and salts.
For hex and Base64 you choose the number of random bytes, and the string length follows from the encoding. For a custom alphabet you choose the character length directly.
It leaves out characters that are easy to confuse: zero, capital O, capital I, and lowercase L. It is common for identifiers people might read aloud or type.
No. They exist only in the page until you copy or leave.