Random String Generator
Generate cryptographically secure random strings, numbers, passwords, and tokens
What is a random string generator?
A random string generator creates unpredictable sequences of characters suitable for passwords, API keys, session tokens, nonces, and unique identifiers. This tool uses the Web Crypto API (crypto.getRandomValues) to draw entropy from your operating system's cryptographically secure random number generator, producing output that is computationally infeasible to predict.
All generation runs entirely in your browser — no strings are transmitted to a server, and no generation history is stored. You can configure the length, choose from predefined character sets (uppercase, lowercase, digits, symbols), add custom characters, and generate multiple strings at once. An entropy indicator shows the strength of each generated string in bits.
How to use Random String Generator
Set the string length
Use the slider or type a number between 1 and 256. Longer strings provide more entropy and stronger security. 32 characters is a good default for most use cases.
Choose character sets
Toggle the character sets you need: uppercase letters (A-Z), lowercase letters (a-z), digits (0-9), and symbols. You can also add custom characters. Use a preset like Alphanumeric, Password, or Hex for quick configuration.
Generate your strings
Strings are generated automatically when you change any setting. Click Regenerate to create new strings with the same configuration. Set the count to generate up to 100 strings at once.
Copy and use
Click the copy icon next to any string to copy it to your clipboard. When generating multiple strings, use the copy-all button to copy all strings separated by newlines.
Frequently asked questions
Is this generator truly random?
Yes. It uses crypto.getRandomValues, which draws from your operating system's cryptographically secure pseudorandom number generator (CSPRNG). This is the same entropy source used by TLS, SSH, and other security protocols. Unlike Math.random(), the output cannot be predicted even if an attacker knows previous values.
What string length should I use?
For passwords, 16-20 characters with mixed character sets provides excellent security. For API keys and tokens, 32-64 characters is standard. For cryptographic nonces or session IDs, 32 characters of hex (128 bits of entropy) or longer is recommended. The entropy indicator below the results shows the strength of your configuration.
Is it safe to generate secrets in the browser?
Yes. All generation happens locally using your browser's built-in crypto API. No strings are sent to any server, and nothing is stored after you close the page. This is safer than server-side generators where your secrets traverse the network. For additional security, consider using the Hash Generator to derive fixed-length hashes from generated strings.
What is entropy and how many bits do I need?
Entropy measures unpredictability in bits. It is calculated as length times log2(charset size). For example, a 32-character alphanumeric string (62 possible characters) provides about 190 bits of entropy. 128 bits is considered very strong for most applications. The tool displays the entropy and a strength rating (Weak, Moderate, Strong, Very Strong) for your current configuration.