Free Random String Generator

What is a Random String Generator?

A random string generator creates unpredictable sequences of characters using cryptographic randomness. These strings are essential for security applications like passwords, API tokens, session IDs, and secret keys.

Our free online random string generator uses JavaScript's built-in Math.random() function to produce alphanumeric strings (A-Z, a-z, 0-9) and optionally includes special characters (!@#$%^&*) for enhanced security. You can customize the length from 1 to 128 characters.

How to Use This Random String Generator

1. Set Length: Use the slider or preset buttons to choose string length (1-128 characters)
2. Choose Options: Check "Include special characters" for stronger passwords
3. Generate: Click "Generate New Random String" or "Regenerate"
4. Copy: Click "Copy" to copy the random string to your clipboard
5. Use: Paste into your application, password manager, or configuration file

Why Use Random String Generation?

For Security

• Password Creation: Generate strong, unpredictable passwords
• API Tokens: Create secure tokens for API authentication
• Session IDs: Generate unique session identifiers
• Encryption Keys: Create secret keys for encryption algorithms

For Development

• Database Seeding: Generate test data for development
• File Naming: Create unique filenames to prevent overwrites
• Temporary Tokens: Generate one-time use tokens for password resets
• CSRF Protection: Create tokens to prevent cross-site request forgery

String Length Recommendations

• 8 characters: Basic tokens, short identifiers (not recommended for passwords)
• 16 characters: API keys, session IDs, temporary tokens (minimum recommended)
• 32 characters: Strong passwords, encryption keys, OAuth tokens (recommended)
• 64 characters: High-security applications, cryptographic keys
• 128 characters: Maximum security, long-term secrets, master keys

Best Practices for Random Strings

• Use longer strings: 16+ characters minimum for security-critical applications
• Include special characters: Increases entropy and makes brute-force attacks harder
• Store securely: Use environment variables or secret managers (never hardcode)
• Rotate regularly: Change API tokens and secrets periodically
• Use HTTPS: Always transmit tokens over encrypted connections
• Hash passwords: Never store plain-text passwords (use bcrypt, Argon2, etc.)

Common Use Cases

For Web Developers

• API Authentication: Generate bearer tokens for REST APIs
• JWT Secrets: Create signing keys for JSON Web Tokens
• CSRF Tokens: Protect forms from cross-site request forgery
• Session Management: Generate unique session identifiers

For DevOps Engineers

• Environment Variables: Create secrets for .env files
• Database Credentials: Generate secure database passwords
• Encryption Keys: Create keys for data encryption at rest
• Webhook Secrets: Verify webhook authenticity (Stripe, GitHub, etc.)

For Security Professionals

• Penetration Testing: Generate test credentials and tokens
• Security Audits: Create sample passwords for strength testing
• Incident Response: Generate temporary access tokens

Frequently Asked Questions

Is this random string generator secure for passwords?

While our generator uses JavaScript's Math.random() which provides good randomness, for maximum security (especially for passwords), we recommend using a dedicated password manager like 1Password, Bitwarden, or LastPass. They use cryptographically secure random number generators (CSPRNGs) certified for security-critical applications.

Our tool is perfect for API tokens, session IDs, test data, and non-critical passwords. For production passwords protecting sensitive data, use a password manager or server-side generation with crypto libraries.

What's the difference between alphanumeric and alphanumeric + symbols?

Alphanumeric strings contain only letters (A-Z, a-z) and numbers (0-9), giving 62 possible characters per position. Adding special characters (!@#$%^&*()_+-=[]'|;:,<>.?) increases this to 87+ characters, dramatically increasing entropy and making brute-force attacks exponentially harder.

For example, a 16-character alphanumeric string has 62^16 possible combinations, while adding symbols increases this to 87^16 combinations—over 1000x more secure.

How long should my API token be?

For API tokens, we recommend at least 32 characters with special characters included. This provides enough entropy to resist brute-force attacks while being manageable for storage and transmission. Popular services like GitHub use 40-character tokens, while Stripe uses 32-character tokens.

Can I use this for cryptocurrency wallet seeds?

No! Cryptocurrency wallet seeds require cryptographically secure random number generators (CSPRNGs) and specific formats (like BIP39 mnemonic phrases). Use official wallet software for generating cryptocurrency keys. Never trust web-based tools for cryptocurrency security.

Does this tool save my generated strings?

No. All string generation happens entirely in your browser using client-side JavaScript. Nothing is sent to our servers, stored in databases, or logged. Your generated strings are private and ephemeral— they exist only in your browser session.

How do I calculate entropy for my string?

Entropy is calculated as: log2(N^L) where N is the character set size and L is the string length. For example, a 32-character alphanumeric string (62 characters) has log2(62^32) ≈ 190 bits of entropy, which is extremely secure (128 bits is considered unbreakable by modern computers).

Should I include special characters for all use cases?

Not always. Some systems (like DNS records, file names, or URL parameters) don't accept special characters. For these cases, use alphanumeric-only strings. For passwords, API keys, and encryption keys where the system supports special characters, always include them for maximum security.