Random string generator

Random text for every occasion

Random strings are the raw material of many small tasks: an API token, a unique id for a record, a coupon code, a temporary key, a test fixture, a cache-busting value, a salt or a filler value for a spreadsheet. Writing a script for each one is overkill, and typing what looks random by hand is not really random. This tool produces as many as you want from the set of characters you choose.

The character sets

• Letters and digits is the general-purpose choice for tokens and ids.
• Hexadecimal gives the 0 to 9 and a to f used in hashes, colour codes and many identifiers.
• Base64 URL-safe uses letters, digits, hyphen and underscore, so the result can go inside a URL without escaping.
• Base32 uses capital letters and the digits 2 to 7, avoiding characters that look alike, which suits codes that people have to read or type.
• Your own characters lets you define the alphabet, for example only certain letters for a coupon code that avoids vowels.

Truly random, and uniform

The randomness comes from your browser's cryptographic random number generator, and each character is picked without the bias that a simple remainder calculation introduces, so every character in the set is equally likely. The tool shows the number of bits of randomness in each string, which tells you how hard one would be to guess: a 16-character string from 62 characters has around 95 bits.

Prefixes, suffixes and no repeats

Add a prefix or suffix to make identifiers such as usr_ followed by the random part. Keep "No repeated strings" ticked to guarantee that every string in the list is different, useful for coupon codes and ids.

What it does not do

The strings are random but carry no meaning and no checksum. If you need passwords, use the password generator, which guarantees character types and rates strength, and for standard identifiers use the UUID generator. Nothing is stored or sent.