Random String Generator
Generate random strings of any length from letters, digits and symbols using cryptographically-strong randomness. Create many at once. Runs in your browser.
How to use Random String Generator: Open Random String Generator — it runs entirely in your browser with no setup. Paste or type your input into the text area, or upload a file where supported. Set any options you need. The result appears in the output panel — there is no upload step and no waiting on a server. Everything runs inside your browser, so your data never leaves your device.
Generate random strings of any length from letters, digits and symbols using cryptographically-strong randomness. Create many at once. Runs in your browser. Random String Generator is a free, browser-based tool in the Filevane generators collection — there is nothing to install, no account to create and no watermark on your results. It works on desktop, tablet and mobile, and because the work happens on your own device it stays fast even with large inputs.
How to use Random String Generator
- Open Random String Generator — it runs entirely in your browser with no setup.
- Paste or type your input into the text area, or upload a file where supported.
- Set any options you need. The result appears in the output panel — there is no upload step and no waiting on a server.
- Review the output instantly; large inputs are handled locally without lag.
- Copy the result to your clipboard or download it. Your data never leaves the page.
Why use Random String Generator?
- 100% free with no limits, no sign-up and no watermarks.
- Private by design — your data are processed in your browser and never uploaded to a server.
- Fast and lightweight, with instant results even on a phone or a slow connection.
- Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
- Part of a full generators suite, so related random string tasks are one click away.
What people use Random String Generator for
- Generating a temporary password, an API key or a test credential.
- Producing a random suffix for filenames or cache-busting.
- Creating sample data for a form or a database seed.
Random String Generator: limits and things worth knowing
- Characters are drawn from the browser's cryptographically secure random number generator, so the output is suitable for credentials — unlike anything based on Math.random.
- Because generation happens on your device, the string is never transmitted. A secret generated by a server has, by definition, been known to that server.
- Length and character set are both adjustable. Excluding visually ambiguous characters (0/O, 1/l/I) is worth doing for anything a human will retype.
- Entropy scales with both length and alphabet size: 16 characters from a 62-symbol set is roughly 95 bits, which is comfortably beyond brute force.
Is it private and secure?
Your privacy is built in. Random String Generator runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.
Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.
You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.
Learn more
Are Online Password Generators Safe? — A password generated on a server has been known to that server. Here's how to tell which generators are safe, and what actually makes a password strong.
Frequently asked questions
Are these strings cryptographically secure?
Yes. They come from the browser's crypto.getRandomValues(), the same CSPRNG used for cryptographic keys — not Math.random(), which is predictable and must never be used for secrets, tokens or passwords.
How long should a random string be?
It depends on the alphabet. With 62 alphanumeric characters, each character adds about 5.95 bits of entropy, so 16 characters gives roughly 95 bits and 22 gives roughly 131. For anything security-sensitive, 128 bits is the usual floor.
Can I exclude characters that look alike?
Yes. Excluding 0/O and 1/l/I is worth doing whenever a human will read the string aloud, retype it, or copy it off a printed page — it costs a little entropy and removes most transcription errors.
Is this suitable for generating API keys?
Yes, provided you use sufficient length. Because generation happens entirely in your browser and nothing is transmitted, no server has ever seen the value — which is the only safe way to produce a secret in a web page.
Related tools
See all free online generators or browse the full tool catalogue.