Uses Web Crypto for secure random characters. Nothing is uploaded.
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Random string & character generator
Generate random characters and strings online—set length and charset, copy securely. Local-first. No signup.
What is a random string / character generator?
What you can do here
Custom character sets: Toggle lowercase, uppercase, numbers, and symbols for each run.
Length control: Generate from short IDs to long tokens (4–128 characters).
Batch generate: Create multiple independent random strings in one click.
Secure randomness: Uses crypto.getRandomValues for unpredictable character selection.
How to generate random characters
Pick length and sets
Enable the character classes you need and set the string length.
Generate
Create one or many random strings with cryptographically strong randomness.
Copy safely
Copy a single result or the full list into your app or password field.
Tips for random strings
- 01
Mix character classes
Include upper, lower, and numbers at minimum for secrets; add symbols when the consumer allows them.
- 02
Prefer longer lengths
Entropy grows with length—16–32 characters beats an 8-character “complex” string.
- 03
Avoid ambiguous output when humans type
If someone must type the string, disable symbols or confusing look-alikes in your own workflow.
- 04
Generate locally for secrets
Local-first generation keeps API keys off third-party servers.
Great for
API keys and tokens
Mint opaque secrets for apps, webhooks, and staging environments.
Test data
Fill forms and fixtures with non-guessable random strings.
Invite and reference codes
Generate codes when you do not need full UUIDs.
Why generate here
Local-first
No upload and no signup—strings stay on your device.
Free to use
Unlimited generations for development and ops tasks.
Crypto-backed
Web Crypto randomness instead of predictable Math.random().
Flexible charset
Match whatever alphabet your API or database allows.
Technical notes
- Entropy source
- crypto.getRandomValues (Web Crypto) supplies random bytes for each character index.
- Bias avoidance
- Rejection sampling maps bytes onto the alphabet without modulo bias.
- Limits
- Length 4–128; batch count 1–50 strings per generate.
- Privacy
- Generation is entirely client-side—nothing is sent to a server.
Sources & References
“The Crypto.getRandomValues() method lets you get cryptographically strong random values.”
MDN — Crypto.getRandomValues(): Browser API used to pick each random character in this generator. developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
“Secrets should be generated with a cryptographically secure pseudo-random number generator.”
OWASP — Password Storage / secrets guidance: Motivates CSPRNG-based token generation instead of ad-hoc or Math.random strings. cheatsheetseries.owasp.org/cheatsheets/Cryptographic_Storage_Cheat_Sheet.html
“Random number generators intended for cryptographic applications must provide output that is unpredictable.”
NIST SP 800-90A: Background on why cryptographic randomness matters for keys and tokens. csrc.nist.gov/publications/detail/sp/800-90a/rev-1/final