Random String Generator

How to use

1. 1Pick an alphabet preset, or choose Custom alphabet and type your own characters. Duplicates are ignored.
2. 2Set the length per string and how many strings you want to generate in one batch.
3. 3Optionally toggle Exclude look-alikes to drop visually similar characters from the active alphabet.
4. 4Use Group every (chars) plus a separator like dash to chunk the output into license-key style groups, and add an optional prefix or suffix.
5. 5Click Generate strings to produce a fresh batch and watch the entropy meter to confirm each string is past the strength threshold you need.
6. 6Use the per-row Copy button to copy a single string, or Copy all to copy the whole list at once.

About this tool

Random String Generator produces cryptographically strong random strings under any alphabet you need. Pick a built-in preset (alphanumeric, lowercase, uppercase, letters, digits, hex lowercase, hex uppercase, base32 RFC 4648, Crockford base32, Bitcoin base58, base62, base64 URL-safe, URL-safe symbols, or full printable ASCII), or type your own custom alphabet. Set the length from 1 to 1024 characters and generate up to 200 strings at once. A toggle excludes look-alike characters (0, O, o, 1, l, I, i, and similar) on presets that do not already exclude them by definition, which is handy when users will read or type the string. A grouping option splits each string into groups of N characters joined with a dash, space, underscore, dot, or slash, which is the classic format for license keys, coupon codes, and one-time codes. Optional prefix and suffix attach after grouping, so tokens like sk_live_AaBb-CcDd-EeFf_v1 are one click away. Every character is drawn with crypto.getRandomValues using rejection sampling, which keeps the distribution uniform across the alphabet even when the alphabet size is not a power of two. The same primitive backs crypto.randomUUID, SubtleCrypto key generation, and TLS in modern browsers, so the randomness here is the same quality you would use to seed an encryption key. A live entropy meter shows bits per string under the active alphabet, so you can verify your length is past the 80 to 128-bit threshold most security guides recommend for tokens that should not be guessable. Useful for generating API tokens, session IDs, webhook secrets, CSRF nonces, short URL slugs, license keys, coupon codes, invite codes, OTP and PIN values, seed data for tests, throwaway database IDs, encryption keys, and any other situation where you need raw randomness rather than a memorable password. Generation, formatting, copying, and entropy math run entirely in your browser. The strings you generate here are never sent to a server, logged, or saved beyond the lifetime of the tab.

Free to use. Works in your browser. No signup, no login.