What can you use random strings for?
Developers and businesses need unpredictable codes all the time: API keys, session tokens, email verification links, invite codes, discount coupons, test data and unique file names. This generator creates them in bulk with exactly the characters and length you need, using cryptographically secure randomness from your browser.
How to use the generator
- Choose a character set, or pick Custom and type your own characters.
- Set the length and how many strings you need (up to 1,000).
- Optionally add a prefix, such as
DIWALI-for coupons orsk_test_for keys, and group characters with dashes to make them easier to read. - Click Generate, then copy or download the list.
Choosing the right character set
| Use | Suggested set | Suggested length |
|---|---|---|
| API key or secret token | Base64URL or letters and numbers | 32 or more |
| Coupon or voucher code | Custom set without 0/O and 1/I | 8–12, grouped |
| Hex ID or salt | Hexadecimal | 32 (128 bits) |
| One-time PIN for testing | Digits only | 6 |
The default custom set, ABCDEFGHJKMNPQRSTUVWXYZ23456789, removes characters that are easily confused when read aloud or typed from a printed card.
How secure are these strings?
Randomness is measured in bits: length × log₂(number of characters). For secrets such as API keys, aim for at least 128 bits, for example 22 Base64URL characters or 32 hex characters. The tool uses crypto.getRandomValues and avoids "modulo bias", so every character is exactly equally likely. Simple generators that use Math.random() are not safe for security purposes.
Frequently asked questions
Can two strings be the same?
With long strings, duplicates are practically impossible. For short codes, like 6 digits, duplicates can happen, so check your list before using it.
How is this different from the password generator?
The Password Generator guarantees a mix of character types for login passwords. This tool gives full control over the alphabet, prefix and format for codes and keys.
Are generated strings stored?
No. They exist only in your browser until you copy them.