API Key Generator
Generate strong random API keys for development and testing. Free online API key generator with prefixes and character sets.
How Does the API Key Generator Work?
Choose a key length, an optional prefix, and a character set, then click Generate to create five random keys at once. Each key is built from cryptographically secure random bytes, so it is strong enough for everyday use as a secret. The prefix (like sk_ or api_) makes keys easy to recognize, and the character set controls how many possible values each character can be.
Example
With a length of 32, an "sk_" prefix, and the alphanumeric character set, a generated key looks like sk_Ab3Xz8mQ2vLp9nW5eR7tY1uK4jF0cH. That key represents about 190 bits of entropy, making it effectively impossible to guess by brute force.
Common Use Cases
- Secrets for authenticating your own applications and services.
- Developer sandbox keys for testing and staging environments.
- Single-use or limited-scope tokens for integrations.
- Random credential values for demo or sample configurations.
FAQs
Which character set should I use?
Hexadecimal uses 4 bits per character, alphanumeric about 5.95, base64 URL-safe exactly 6, and the symbol set a bit more. Larger character sets give more entropy for the same length, but some systems restrict special characters, so pick a set that is accepted by wherever you will use the key.
How long should my key be?
Aim for at least 128 bits of entropy — that means about 32 hex characters, 22 alphanumeric characters, or 22 base64 characters. The default of 32 alphanumeric characters is comfortable for most uses.
Are these keys secure?
Keys are generated with Web Crypto random values in your browser, so they are cryptographically strong. Still, a strong key is only as safe as how you store it — never commit keys to version control or expose them in client-side code.