Cryptographically secure API key/secure token batch generation generator | ZeroTools

Generate random strings in formats including Hex, Base64, and UUID v4. Adjust length and select character sets for custom alphanumeric formats.

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When to use this tool

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Generate random tokens in hex, Base64, Base64URL, UUID, or a character-set format.

Try it first

Choose Hex, length 16 bytes, and quantity 2. Generate again and check for two 32-character strings.

Before you start

Length units vary by format. Generated tokens are displayed on screen; secure storage and revocation are separate tasks.

Local Token Generation

Token generation runs locally in your browser using the Web Crypto API. The strings are not transmitted externally during generation, though site assets, analytics, and advertisements may communicate separately.

ZeroTools: Browser Processing & Privacy

ZeroTools focuses on tools that process input on your device. Check each tool’s scope and limitations before use.

Processing and privacy policy
Article Index
Ch. 1Choose a format and lengthCh. 2How custom alphabets workCh. 3Randomness and credential handling
Chapter 1

Choose a format and length

Hex, Base64 and Base64URL encode the selected number of random bytes. For example, 32 bytes produce 64 hexadecimal characters. Base64URL uses URL-friendly characters without padding.

Alphanumeric and custom modes measure length in characters. UUID mode produces a fixed-format version 4 identifier.

Chapter 2

How custom alphabets work

Custom mode uses only the supplied characters and treats repeated characters as one choice. An empty alphabet stops generation. Character selection avoids modulo bias, but does not guarantee that every selected character category appears in each token.

Chapter 3

Randomness and credential handling

Randomness comes from Web Crypto on your device; generation stops if it is unavailable. This tool does not register credentials, set expiry dates, grant permissions or mask displayed tokens.

Check where you copy or save the output.

Frequently Asked Questions (FAQ)

A.
Hex, Base64 and Base64URL use source bytes. Alphanumeric and custom modes use characters. UUID v4 has a fixed length.
A.
Generation stops and previous results are cleared. Repeated characters count as one choice. Changing the alphabet updates the output.
A.
No. This generates a string, not a registered credential. Registration, permissions, expiry and storage must be configured in the receiving system.
A.
The estimate uses the selected length and character set. Use the result in a system that protects secrets and enforces its own scope, expiry and access rules.

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