Random String Generator
Generate random strings with custom lengths and character sets.
- Free
- No signup
- Runs in your browser
How it works
How to use
Set length, quantity, character sets, and optional exclusions.
Method
Unbiased secure sampling selects every character locally.
Example
Generate three 16-character strings without ambiguous characters.
The alphabet decides what every position is allowed to become
Random String Generator starts by building one alphabet from the character classes you enable. Lowercase contributes a-z, uppercase contributes A-Z, numbers contribute 0-9, and symbols contribute !@#$%^&*()-_=+[]{};:,.?.
Each output position is then sampled from that combined alphabet. Choose the alphabet for the field that will receive the result: a test fixture can tolerate characters that may be inconvenient in a URL, filename, printed code or manually typed identifier.
selected character sets
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combined alphabet
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random draw for position 1
random draw for position 2
random draw for position 3
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repeat until requested lengthSelected does not mean guaranteed to appear
Enabling Numbers makes digits eligible for every draw; it does not require every generated string to contain a digit. A short result sampled from lowercase letters and numbers can legitimately contain only letters.
This differs from SnakTool's Password Generator, which deliberately places at least one character from every selected class before shuffling. Random String Generator samples each position independently from the combined alphabet instead.
Exclude look-alikes when a person has to read the result
The ambiguous-character option removes 0, O, o, 1, l and I from the combined alphabet. Those shapes can be inconvenient when a value must be read from paper, spoken aloud or typed manually.
The option only removes ambiguous characters that are present in the classes you selected. It does not otherwise rewrite the generated string or guarantee that the result will be easy to distinguish in every font.
0 O o 1 l IRemoving characters improves readability by shrinking the sample space
Ambiguous-character exclusion is a usability tradeoff, not a free security upgrade. Removing characters makes the alphabet smaller, which reduces the number of possible strings for the same length.
That can be worthwhile when transcription errors matter. When humans never need to read the value, decide from the receiving system's constraints rather than assuming that fewer look-alike characters automatically makes the random value stronger.
Length multiplies possibilities instead of adding them
For independent draws from an alphabet of A characters, a string of length L has A raised to L possible sequences. Adding one position therefore multiplies the space by the alphabet size rather than adding a fixed number of possibilities.
SnakTool accepts lengths from 1 through 1,024 characters. A one-character output can be perfectly valid for a test or random choice; unlike a password generator, this tool's minimum length is not intended as an account-security recommendation.
possible strings = alphabet_size ^ lengthGenerating 100 strings does not reserve 100 unique values
Quantity controls how many independent strings are generated in one run, from 1 through 100. SnakTool does not keep a global registry of previous outputs or retry a batch until every value is different.
Two generated strings can therefore be identical. If an application requires uniqueness, enforce that requirement where the identifiers are stored or issued instead of treating random generation itself as a uniqueness constraint.
A collision is possible even when every draw is fair
Collision risk depends on the size of the possible-output space and how many values are issued from it. A tiny alphabet and short length can produce duplicates quickly; a larger space makes collisions less likely without making them mathematically impossible.
This is why random and unique are different properties. Increasing length can expand the available space dramatically, but a database identifier still needs whatever duplicate handling or uniqueness constraint the application requires.
Secure randomness decides the draw, not where the result is valid
SnakTool selects characters using the browser's crypto.getRandomValues() source through a secure integer helper. That helper uses rejection sampling rather than a direct modulo mapping, avoiding modulo bias when a random range does not divide evenly into the alphabet size.
Cryptographic randomness describes how the character is selected. It does not mean the resulting text is valid in every protocol, field or application; the destination still decides which characters and lengths it accepts.
crypto.getRandomValues()
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secure integer with rejection sampling
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index in selected alphabet
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characterSymbols can make a random string unsuitable for its destination
The symbol alphabet includes characters that have special meaning in contexts such as URLs, query strings, shells or other syntaxes. A cryptographically random output is not automatically a URL-safe, filename-safe or syntax-safe token.
Restrict the selected classes when the destination expects a narrow alphabet, or apply the destination's proper encoding rules afterward. Randomness should not be used as a substitute for contextual escaping or validation.
A random string is new data, not an encoding of existing data
Base64 and URL encoding transform existing bytes or text into another representation. Hashing deterministically derives a digest from an input. Random String Generator instead creates new characters by random sampling.
That difference matters when choosing a tool: generating an alphanumeric value does not make it Base64, and a random-looking string is not evidence that an input was hashed or encrypted.
Production tokens need a lifecycle around the random value
A cryptographically random string can be one ingredient in a token design, but production API keys, session tokens and recovery secrets need more than random characters. Their systems also have to define sufficient entropy, storage, expiration where appropriate, rotation, revocation, transport and authorization behavior.
Use this generator when its alphabet and length match the task, but do not treat a generated string alone as a complete authentication or token-management system.
Frequently asked questions about Random String Generator
Does every selected character type appear in every random string?
No. Selected classes are combined into one alphabet, and every position is sampled independently from that alphabet. A selected class can therefore be absent from a particular result.
Are generated random strings guaranteed to be unique?
No. Each string is generated independently and SnakTool does not reserve previous outputs or retry until a batch is duplicate-free. Enforce uniqueness separately when an application requires it.
What is a random string?
A random string is a sequence whose characters are sampled from a chosen alphabet. In SnakTool, you choose the allowed character classes, length and quantity before generation.
Can I generate numeric random strings?
Yes. Select Numbers alone to generate strings whose positions are sampled from digits 0 through 9.
What is rejection sampling in this generator?
The secure integer helper discards random values outside a clean divisible range before mapping a value to an alphabet index. This avoids the small bias that a direct modulo mapping can introduce.
Is a random string the same as a UUID?
No. A UUID has a defined identifier format and version semantics. Random String Generator produces characters from the alphabet and length you configure without giving the result UUID structure.
Can I use the output as a session token?
Do not treat random characters alone as a complete session design. Session systems need appropriate entropy plus secure issuance, storage, cookie or transport settings, expiration, rotation and invalidation behavior.
Does SnakTool guarantee one character from every selected set?
No, not in Random String Generator. That guarantee belongs to the Password Generator; this tool independently samples from the combined selected alphabet.