Random String Generator
Create random strings for codes, identifiers, test data or coupons. Choose the length, the character sets or your own exact alphabet, add a prefix or suffix, and generate up to 1,000 strings at once, optionally all different. Characters are chosen without bias by your browser’s cryptographic random generator.
- Runs in your browser
- No sign-up
- Free to use
How to use Random String Generator
- Set the length and how many strings you need.
- Choose the character sets, or type your own alphabet.
- Add a prefix or suffix and decide whether duplicates are allowed.
- Generate, then copy or download the list.
Random String Generator features
Any alphabet
Letters, digits, symbols, or exactly the characters you type, including Unicode.
Batch output
Up to 1,000 strings of up to 1,024 characters.
Unique option
Guarantees no duplicates in the list.
Prefix and suffix
For codes such as PROMO-XXXX-2026.
Unbiased randomness
crypto.getRandomValues with rejection sampling.
Randomness shown
Bits per string from the alphabet and length.
When to use Random String Generator
- Generating coupon or voucher codes.
- Creating test data for databases and forms.
- Making random file or object names.
- Producing short reference codes.
Random String Generator FAQ
Are the strings random enough for passwords or keys?
The randomness is cryptographic. Whether a string is strong enough depends on its length and alphabet; the bits figure tells you. For secrets aim for 128 bits, which the Random Token Generator makes easy.
Can I use characters from other languages?
Yes. Type them in the “exactly these characters” field; each is treated as one character, including emoji.
How does the unique option work?
Duplicates are discarded and replaced until the list has the requested number of different strings. The tool warns if the alphabet and length allow too few combinations.
Are the strings stored?
No. They are generated in your browser and exist only on this page.
What are look-alike characters?
Characters easily confused when read: I, l, 1, O, 0, o and a few quotes. Leaving them out helps for codes people type by hand.
Is there an API?
No. Everything happens in the browser, which keeps the strings private.
Randomness on demand
Random strings are everywhere in software and business: order references, voucher codes, temporary file names, test fixtures, invitation codes. Each use has its own requirements on length and characters, which is why this generator lets you specify both freely, including an exact custom alphabet.
Quality of randomness matters even when the strings are not secrets. Generators based on Math.random can produce patterns and repeats, and some are predictable from earlier output. This tool uses the browser’s cryptographic generator with rejection sampling, so every character in the alphabet is exactly as likely as every other.
The bits figure helps judge whether a string is long enough for its job. Codes that people type, such as vouchers, can be short if they are checked against a database and attempts are limited. Anything that grants access on its own, such as a password-reset link token, needs at least 128 bits so it cannot be guessed.
For human-readable codes, remove look-alike characters and keep the alphabet to upper-case letters and digits; the Crockford Base32 set is a good example. For machine identifiers, longer strings from a large alphabet are fine.