Random String Generator

Random String Generator — Free random string generator. Generate 1–100 random strings of any length with custom character sets — uppercase, lowercase, digits, symbols. Exclude similar-looking characters. Uses Web Crypto API for true randomness. No signup required.

Length

Count

1 string · 16 chars each

GEvzzHNKWj5vR9vf

What are random strings used for?

Random strings are fundamental building blocks in software development and security. Any time you need an unpredictable, unique sequence of characters — an API key, a session token, a one-time code — a random string generator is the tool for the job.

API keys — authenticate clients to your service (32–64 chars recommended)
Session tokens — identify authenticated user sessions securely
Temporary passwords — one-time credentials for account setup or resets
Secret keys — HMAC signing keys, encryption keys, webhook secrets
Test data — fill databases with realistic-length random values for load testing
Nonces — single-use values to prevent replay attacks in cryptographic protocols

Choosing the right character set

A–Z + a–z + 0–9 — alphanumeric only, URL-safe, works in any context. Good default for most use cases.
+ Symbols (!@#...) — maximum entropy per character. Use for passwords and secret keys where the string never needs to be typed by hand.
Exclude similar characters — removes i, l, 1, L, o, 0, O. Essential for activation codes and temporary passwords that users read from a screen.

Why length matters more than character set

A 32-character alphanumeric string has 62³² ≈ 2²×10⁵⁷ possible values — effectively impossible to brute-force. Adding symbols increases entropy per character, but doubling the length has a far larger effect on security. For most applications, a 32-character alphanumeric string is more than sufficient. Use 64+ characters only when the spec explicitly requires it.

Frequently Asked Questions

What is a random string used for?

Random strings are used for API keys, session tokens, temporary passwords, unique identifiers, test data generation, CAPTCHA codes, secret keys, nonces in cryptography, and any situation where you need an unpredictable sequence of characters.

Is this cryptographically random?

Yes. This generator uses the Web Crypto API (crypto.getRandomValues), which produces cryptographically secure random numbers directly in your browser. This is the same level of randomness used for security-sensitive applications. No data is sent to any server.

What length should I use?

For API keys, 32–64 characters is standard. For session tokens, 32 characters minimum. For temporary passwords, 12–20 characters. For identifiers where human readability matters, 8–12 characters with similar characters excluded. For maximum security, use 64+ characters.

What does "exclude similar characters" do?

This option removes characters that look alike in certain fonts: i, l, 1, L, o, 0, O. This reduces ambiguity when strings need to be read or typed manually — for example, in activation codes or temporary passwords you show to users.

What is the difference between a random string and a UUID?

A UUID (Universally Unique Identifier) follows a specific format (8-4-4-4-12 hexadecimal characters) designed for database primary keys and distributed systems. A random string has no fixed format and is more flexible — better for API keys, tokens, and passwords where format does not matter.