What format should I use for API keys?

Hex and Base64url are common for API keys. Hex is case-insensitive and URL-safe. Base64url is more compact (fewer characters for the same entropy). Alphanumeric is easiest to read and communicate verbally.

How much entropy do I need?

For API keys used in production, 128 bits (32 hex chars) is the minimum; 256 bits (64 hex chars) is standard. For session tokens, 128 bits is generally sufficient.

What is the difference between a token and a UUID?

UUIDs (v4) have 122 bits of randomness and a standard format (8-4-4-4-12 hex). Tokens can be any length and format. UUIDs are better for database primary keys; custom tokens are better for API keys where format is flexible.

Is Base64url different from standard Base64?

Base64url replaces + with - and / with _, and omits padding (=), making tokens URL-safe without percent-encoding. Use Base64url for tokens that appear in URLs, headers, or cookie values.

Token & API Key Generator

Generates cryptographically secure random tokens and API keys using the browser's crypto.getRandomValues() API. Choose from hex (128-bit to 512-bit), Base64url, alphanumeric, and custom character set formats. Generate multiple tokens at once for bulk key provisioning.

Runs entirely in your browser — your input is never uploaded, stored, or logged.

Choose your token format and length, then generate secure random keys for your applications. To generate HMAC signatures using your token as a secret key, use the HMAC Generator.

Examples

256-bit hex token

Input

256-bit hex

Output

a3f8e2b1c4d9e0f5a1b2c3d4e5f60718...

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