Random String Generator

What Is the Random String Generator?

This tool generates a random string of any length, drawing from either the default alphanumeric character set (A-Z, a-z, 0-9) or a custom character set you specify -- useful whenever you need random text that isn't structured as a UUID or password specifically.

How to Use This Tool

Set a length and, optionally, a custom character set. Click Generate for a fresh random string.

How the String Is Generated

Practical Uses

• Generating a random test identifier or placeholder value
• Creating a random string from a custom alphabet (e.g. only certain letters or symbols)
• Generating sample data for testing string-length or format handling

For an API-key-shaped random token with a prefix, see the API Key Generator. For a cryptographically strong password specifically, use the Password Generator.

Designing a Character Set

The Character Set field is treated as a list of individual characters, and each position in the output is chosen independently from that list. The default is all uppercase letters, lowercase letters and digits, which is 62 characters. You can replace it with anything: type 0123456789 for numeric codes, ABCDEF0123456789 for hexadecimal-style strings, or a short set such as ABCDEFGHJKMNPQRSTUVWXYZ23456789 to avoid look-alike characters like the letter O and the digit 0. Smaller sets are easier to read aloud but need more length to stay hard to guess.

Repeated Characters Change the Odds

Because the tool picks a random position in the text you typed, a character that appears several times has a proportionally higher chance of being chosen. If your set is aab, the letter a is twice as likely as b. This can be used deliberately to weight results, but if you want each symbol equally likely, list each one only once. There is no de-duplication step, so cleaning the set is your responsibility.

A Worked Example: Invite Codes

Suppose you want eight-character invite codes that people can type from a printed card. Set the length to 8 and enter a character set of uppercase letters and digits without the confusing characters 0, O, 1, I and L. That leaves 31 usable characters, so there are about 850 billion possible codes (31 to the eighth power). Generate several times to get a batch, copy each, and record them somewhere safe, since the tool does not remember previous results. Before using codes in a real system, check for duplicates in your database, because random independent draws can collide.

Limits and Cautions

• Length accepts values from 1 up to 500. A length below 1 is raised to 1.
• An empty character set produces an error message rather than an empty string.
• Characters outside the basic multilingual range, such as some emoji, are made of two code units, so they may be split apart and produce broken symbols. Stick to ordinary letters, digits and punctuation for reliable results.
• The tool generates one string at a time and gives no guarantee that every character type appears; use the password generator when you need at least one of each type.
• Changing the length or character set re-rolls automatically, so copy your string before editing settings.

The randomness comes from the browser cryptographic source, so the strings suit tokens, test data and identifiers. Whether a given string is appropriate as a real security credential depends on your application and threat model, which is a decision for your security team or documentation.

Frequently Asked Questions