Random String Generator
Generate random strings for security tokens, passwords, API keys, and more.
Input Information
Result
Please generate a strings.
Random String Generator A tool that instantly creates random strings for use as security tokens, passwords, API keys, temporary IDs, and more. Select needed character types (uppercase, lowercase, numbers, symbols) and set length and count to generate high-quality strings using cryptographically secure algorithms.
Useful for temporary password issuance, session/auth token creation, test dummy data, collision-free filenames, and more across development and operations.
Essential for developers and service operators, and useful for general users as a secure password creation tool. Generated strings can be copied directly to clipboard.
This tool uses the Web Crypto API (crypto.getRandomValues), making values harder to predict than regular random numbers. Generated values are only displayed on screen and not stored, so save important keys separately.
- Set the length of the string (1-256 characters).
- Choose the character set to use (uppercase, lowercase, numbers, symbols).
- Enter how many strings to generate and click generate.
- Copy individual strings or copy them all.
8-Character Alphanumeric
Choose length 8 with uppercase, lowercase, and numbers to generate exactly 8 alphanumeric characters, e.g. Kx9mQ2pZ.
16 Characters with Symbols
Choose length 16 with all character types to generate a strong 16-character string containing symbols, e.g. A#b9!kD$f2@Lm4&Q.
Length Limit
Length is limited to between 1 and 256. Values outside this range are automatically clamped to the nearest allowed value.
Charset Composition
Creates the available character set based on selected character types.
uppercase + lowercase + numbers + symbols
Possible Combinations
With length L and charset size N, the total possible strings are:
Combinations = N^L
Example: 62 characters, length 16 → 62^16 ≈ 4.7×10²⁸
Random Mapping
Uses the remainder of a random integer divided by charset length as the index.
result += charset[random % charset.length]
This guarantees a uniform distribution where each character has equal probability of selection.
Password Length
- Use at least 12 characters for important accounts, 16+ recommended.
- Enabling all character types increases strength.
API Key Generation
- Special characters may cause escaping issues, so numbers+letters combo is recommended.
- Session/auth tokens of 32+ characters are recommended.
No Reuse
- Don't reuse the same string across multiple places.
- Replace immediately if a leak is suspected.
Safe Storage
- Generated values are not stored, so use a password manager.
- Be careful not to leave traces in screenshots or logs.
Test Data
- Use bulk generation for dummy data and filename creation.
- Up to 50 can be generated at once.
Complexity Control
- Adjust symbol inclusion based on usage.
- Numbers+letters combo is suitable when readability is needed.
QWhat character sets are available?
You can combine uppercase (A-Z), lowercase (a-z), numbers (0-9), and special symbols such as !@#$%^&*. If none are selected, lowercase letters are used by default.
QIs this generator cryptographically secure?
Yes. Unlike Math.random(), this generator uses crypto.getRandomValues() to provide cryptographically secure randomness.
QWhat length is recommended for passwords?
A length of 16 characters or more, ideally including symbols, is recommended for passwords. Longer strings are far more resistant to guessing and brute-force attacks.
QWhat is the probability of duplicate strings?
With a character set of size n and length L, there are n raised to the power of L possible combinations. With sufficient length and variety, the probability of duplicates is extremely low.
QWhat can I use these strings for?
These strings are ideal for passwords, API keys, auth tokens, session IDs, and one-time codes wherever strong randomness is required.