Random String Generator

Random String Generator

Generation runs locally in the browser using cryptographic random integers with rejection sampling.

Set an integer length from 1 to 10000 and an integer count from 1 to 1000. A nonempty custom alphabet replaces all checkboxes. If it is empty, the checked built-in sets are used; only an empty effective alphabet is rejected. The built-in sets omit I, O, l, 0 and 1. Add those characters through the custom field; there is no ambiguity checkbox here.

Length and custom alphabet size count Unicode code points, not visible grapheme clusters. The custom alphabet is limited to 10000 code points; repeated entries retain their probability weight. With AAB, each position has probability 2/3 for A. Each position is drawn independently with replacement, so strings can repeat and a selected group may be absent. There is no strength estimate or uniqueness mode.

A conservative output budget of 1000000 UTF-16 code units includes line breaks and assumes every position uses the longest character in the alphabet. A count and length individually within range can therefore still be rejected. Copy saves the text; there is no file download.

Possible example: alphabet AB, length 4, count 2.

ABBA
BAAA

ABCDEFGHJKLMNPQRSTUVWXYZ
abcdefghijkmnopqrstuvwxyz
23456789
!@#$%^&*()-_=+[]{}?