100% Client-Side Privacy • Cryptographically Secure (CSPRNG)

Instant Random String & Password Engine

Generate randomized sequences, strong passwords, API tokens, OTP codes, and UUIDs directly in your browser using the Web Cryptography API. Your generated keys never touch any external server.

Web Crypto API (crypto.getRandomValues) Bulk Generation (Up to 5,000 strings) Custom Patterns, Masks, Prefixes & Suffixes 1-Click Export to Excel, CSV, JSON & Clipboard

Generator Settings

Quick Presets

String Length 16 chars

Quick:

Batch Quantity Max 5,000

strings

Quick:

Character Sets

Uppercase A – Z

Lowercase a – z

Numbers 0 – 9

Symbols !@#$%^&*

No Ambiguous Exclude 0, O, 1, l, I

Custom Chars Add user characters

Formatting & Pattern Masks

Security & Entropy

Cryptographically Secure (CSPRNG) Uses hardware entropy via window.crypto

Ensure Uniqueness Zero duplicate strings in batch

Shannon Entropy Strong (104 bits)

Generated Output

10 strings

Strong Password

16 characters including uppercase, lowercase, numbers, and symbols. Cryptographically secure.

API Secret Key

32 characters alphanumeric token ideal for REST APIs, Bearer headers, and webhook endpoints.

UUID (v4 Format)

Standard 36-character hexadecimal GUID format: 8-4-4-4-12 characters.

6-Digit Numeric OTP

Strictly numeric digits (0-9) formatted for SMS authentication, verification codes, and PINs.

Hexadecimal Hash

64 characters hex sequence (0-9, a-f) simulating SHA-256 hashes and cryptographic salts.

Clean Alphanumeric

Letters and numbers without ambiguous punctuation. Perfect for license keys and invite codes.

Understanding String Entropy & Cryptographic Randomness

Random strings are fundamental to cybersecurity, database indexing, user authentication, and distributed software architecture. Here is a breakdown of how entropy and cryptographic randomness protect your systems:

Shannon Entropy Formula

Entropy measures the unpredictability of a generated sequence, calculated as:

Entropy (Bits) = L × log₂(R)

Where L is string length and R is the character pool size. For example, a 16-character alphanumeric string draws from 62 possible characters, yielding over 95 bits of entropy.

Web Crypto API (CSPRNG)

Unlike standard Math.random() (which uses pseudo-random algorithms susceptible to seed prediction), this tool uses:

window.crypto.getRandomValues(new Uint32Array(len))

This accesses operating system hardware entropy (CPU jitter, system events) ensuring high-grade unpredictability suitable for cryptographic secrets.

No, absolutely not. This generator is 100% client-side. The generation logic runs purely inside your browser JavaScript runtime. No strings, keys, or patterns are ever transmitted over the network or saved on our servers.

A cryptographically secure password has high entropy (minimum 80 bits), includes a diversified character set (uppercase, lowercase, digits, and symbols), and is generated using a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) rather than predictable pseudo-random seeds.

You can define a format such as PROMO-999-AAA where 9 is replaced with random digits, A with uppercase letters, a with lowercase letters, and * with any alphanumeric character. Fixed characters like hyphens remain intact.

Free Random String Generator