BrowserTools

Random String Generator

Custom-character random strings, any length

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-09-21
Free Private No uploads
What is Random String Generator?

Four Character set options decide what the string is built from: lowercase letters only, upper and lower letters, letters plus digits, or the full set adding fourteen punctuation characters. Length runs from 1 to 512 and Count from 1 to 500, so you can ask for a single 512-character blob or five hundred 8-character identifiers in one pass. Each position is filled from a Uint32Array that crypto.getRandomValues populates, which makes this the right generator for tokens, slug material, API test keys and anything else where you want a defensible source of bits. One honest caveat: the final character is chosen with a remainder, so with a pool of 62 or 76 the first few characters are very slightly favoured over the rest — irrelevant for test data, and worth remembering if you are minting a real session secret.

Build random strings from exactly the character sets you choose — letters, digits, symbols or your own custom alphabet. The workhorse for IDs, tokens, slugs and test data.

Private Random String Generator In Your Browser

Random String Generator is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Random String Generator

1

Choose a Character set: lowercase letters, upper and lower letters, letters and digits, or letters, digits and symbols.

2

Set Length between 1 and 512 and How many? between 1 and 500.

3

Press Generate.

4

Copy the block — each line is one independent string of the length you set.

Key Capabilities
  • Four character sets spanning 26, 52, 62 and 76 possible characters.
  • String length from 1 to 512 characters, and 1 to 500 strings per batch.
  • Bits come from crypto.getRandomValues, so this is suitable for tokens and test keys.
  • Length is clamped rather than rejected, so a stray zero produces a one-character string instead of an error.
Common Use Cases
  • A backend developer seeding a session table needs five hundred sixteen-character keys.
  • A QA engineer building slug-uniqueness tests needs two hundred strings from a deliberately narrow pool.
  • A front-end developer writing a password strength meter needs fixed-length inputs with and without symbols.
Clear Answers

Frequently Asked Questions

Is the distribution perfectly even across characters?
Very nearly, but not exactly. Each value is taken as a remainder against the pool size, and a 32-bit draw does not divide evenly by 76, so characters early in the pool are fractionally more likely. For fixtures this is invisible; for a production secret, prefer a purpose-built library.
Which set should I use for a share link slug?
Letters and digits, at a length of six or more, is the usual choice because the result stays unambiguous in a URL and when read aloud. Adding symbols means every slug needs percent-encoding.
What if I enter a length of zero?
The value is clamped up to 1 rather than rejected, so you get a single character instead of an error message. The same clamping applies to the batch count.