Set your options, generate instantly.
Pick a length and character set, add an optional prefix or suffix, and choose how many strings you need. Everything is generated locally with your browser's secure random number source — nothing is ever sent anywhere.
Any character typed here is removed from the pool before a string is built.
Added once at the very start of every generated string.
Added once at the very end of every generated string.
Four steps, a string you can trust.
No manual required — here's the entire flow.
Set the length
Drag the slider or tap a preset — anywhere from 1 to 256 characters. Longer strings mean more entropy and stronger security.
Choose character types
Toggle uppercase, lowercase, numbers and symbols independently. At least one type must stay on. Add a prefix or suffix if you need one.
Generate
Tap Generate Strings to get a fresh batch. Not happy with the results? Tap Regenerate to try again with the same settings.
Copy or download
Copy a single string, copy the whole batch, or download it as a text file. Entropy and estimated crack time are shown alongside.
Built for real security, not just randomness.
The details that make a random string generator trustworthy, without ever leaving your browser.
Runs on your device
Every string is generated locally using the Web Crypto API. Nothing is logged, saved, or sent anywhere — ever.
Entropy & crack time
Every result comes with a plain-language strength rating so you know exactly how tough it is to guess.
Fine-grained control
Exclude ambiguous characters, require every type at least once, block specific characters, and add a prefix or suffix your system needs.
Questions people actually ask.
The short answers — with the long ones one tap away.
How do I generate a random string with this tool?+
Set a length, choose which character types to include, optionally add a prefix or suffix and turn on any advanced rules you want. Then tap Generate Strings. Your results appear on the right, each with its own copy button.
Are my random strings sent to a server?+
No. Every string is generated locally in your browser using the Web Crypto API, and nothing is ever uploaded, logged or stored. Closing or refreshing the page clears everything.
What is a cryptographically secure random string?+
A cryptographically secure random string is generated using a source of randomness that is unpredictable enough for security purposes, such as the Web Crypto API. This makes it suitable for tokens, session IDs, API keys and passwords, unlike strings built from Math.random().
What do entropy and estimated crack time mean?+
Entropy measures how many possible combinations a string could have, in bits — more bits means more guesses needed. Estimated crack time turns that number into a rough duration, assuming a fast offline guessing attack.
Can I exclude characters that look alike, like 0, O, 1 and l?+
Yes. Turn on Exclude ambiguous characters to drop easily confused characters, or list your own characters to avoid in the custom exclusions field.
Can I add a prefix or suffix to every generated string?+
Yes. Type a prefix and/or suffix in the dedicated fields and every generated string will start and/or end with exactly what you entered, while the random part stays fully random.
Can I generate more than one random string at a time?+
Yes. Choose a quantity of 1, 5, 10, 25, 50 or 100 and every string in the batch is generated independently with the same settings, so you can pick the one you like or copy them all.
Does this tool store or remember any string I generate?+
No. Nothing is saved, logged or synced anywhere. Once you leave or refresh the page, every generated string is gone for good — copy or save the ones you want to keep.
Is this random string generator free to use?+
Yes, it's completely free with no account, no sign-up, and no limit on how many strings you generate.