Random character generator

How it works

The tool holds a set of allowed characters and draws from that set. One draw is one glyph. A string is several draws in a row. If the set is “uppercase English letters,” you will never see a digit. If the set includes punctuation, you will see punctuation. The generator does not know what you meant the string for. It only knows the set and the length.

Most on-screen versions are pseudorandom: an algorithm that is hard to predict by eye. That is enough for a dummy serial, a test username, a game code, or a writing prompt made of letters. It is the wrong instrument for a cryptographic key unless the page is built and audited for that job. A toy that prints pretty strings is still a toy.

Repeats inside a string are allowed on independent draws. A double letter can be honest. If you need each glyph unique inside one string, that is sampling without replacement from the set, and the string cannot be longer than the set. Say which rule you wanted. Do not call a double “l” a bug in a with-replacement draw.

Building a string, not a person

The word “character” in this tool means a glyph: a letter, a digit, a mark. It does not mean a protagonist with a backstory, and it does not mean a role-playing sheet with stats. Those are other generators with other lists. If you opened this page to name a hero, you want a word or name list. If you opened it to fill a password field, you want length and a mixed set, then a vault to store the result, because you will not remember a true random string.

Choose the alphabet: letters only, letters and digits, or a wider set. Choose the length. Longer strings from a larger set are harder to guess; that is the point of a secret, not of a prompt. Choose whether order and case matter. They do.

Draw once, copy once, and save it if it is a secret. Drawing again is a different string. Ambiguous glyphs cause practical pain. A set that mixes uppercase I, lowercase L, and the digit 1 will produce strings that people misread on paper. If a human has to type the result, drop the look-alikes or use a font that distinguishes them. If only a machine will store the result, the look-alikes are fine.

Length, alphabet, and what “random” is not

A short string from a tiny set is easy to write down and easy to guess. A long string from a wide set is the opposite. Padding a chosen word with a random mark at the end is not a random character string; the word is still the word. If you want the generator to work, let it pick every position.

A random character is a glyph. If you wanted a protagonist, you opened the wrong drawer. Do not paste a generated secret into a chat log, a screenshot album, or an unencrypted note. The generator’s job ended when it showed the glyphs. Storage is a different tool. If you are only making a dummy invoice number, none of that caution applies: make it, use it in the mock, throw it away.