Random String Generator
Generate secure random strings, passwords, and codes instantly. Customise length and character sets for perfect results every time.
Configure your options and press Generate to create random strings.
Entropy: 71.5 bits — pool: 62 chars
Advanced options
What is a Random String Generator?
A random string generator is a crucial security tool that creates unpredictable sequences of characters for passwords, API keys, unique identifiers, and cryptographic tokens. Our advanced password generator uses cryptographically secure randomness with customisable character sets, length controls, and entropy analysis to ensure maximum security for your digital assets. This free online tool generates everything locally in your browser for complete privacy.
How to use this generator
- Set your string length using the slider (1–128 characters)
- Choose character types — uppercase, lowercase, numbers, symbols, or custom characters
- Configure advanced options like excluding similar characters and setting the count
- Generate and copy your secure strings with one click
Common Uses for Random String Generation
Security & Authentication
- Strong password creation
- API key generation
- Session token creation
- Cryptographic salt generation
Development & Programming
- Database record IDs
- Unique filename generation
- Test data creation
- Random string constants
Gaming & Applications
- Game lobby codes
- Invitation codes
- Temporary access codes
- Random seed generation
System Administration
- Temporary password creation
- Configuration tokens
- Backup encryption keys
- System identifiers
Understanding Password Strength and Entropy
Password entropy measures the unpredictability of a password in bits. Higher entropy means more possible combinations, making passwords exponentially harder to crack. Our generator calculates entropy based on your character set size and string length, helping you create cryptographically secure passwords and keys.
Entropy levels
- 60+ bits: Very Strong (recommended)
- 40–59 bits: Strong (acceptable)
- 25–39 bits: Moderate (basic security)
- 15–24 bits: Weak (avoid for important use)
- <15 bits: Very Weak (not secure)
Character pool sizes
- Lowercase only: 26 characters
- Mixed case: 52 characters
- Mixed + numbers: 62 characters
- Mixed + numbers + symbols: 94 characters
- Custom sets: Variable pool size
Best Practices for Secure String Generation
For Passwords
- • Use at least 12 characters for good security
- • Include mixed case, numbers, and symbols
- • Avoid similar-looking characters if sharing
- • Aim for 60+ bits of entropy
For API Keys
- • Use 32+ characters for high security
- • Include alphanumeric characters
- • Consider excluding symbols to avoid encoding issues
- • Generate unique keys for each service
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Frequently Asked Questions
Q.How secure are the generated strings?
Our generator uses cryptographically secure randomness and provides entropy analysis. Strings with mixed character types and longer lengths provide better security.
Q.What character types can I include?
You can include uppercase letters, lowercase letters, numbers, symbols, or provide custom characters. You can also exclude similar-looking characters for better readability.
Q.Can I generate multiple strings at once?
Yes! You can generate up to 50 strings simultaneously, making it perfect for creating multiple passwords or unique identifiers in bulk.
Q.What is password entropy and why does it matter?
Entropy measures password strength in bits. Higher entropy means more possible combinations, making passwords harder to crack. Our tool calculates entropy to help you create secure strings.