API Key Generator

About API key generator

Creates random API keys with a prefix, an alphabet and length you choose, and can append a checksum so your server can reject mistyped keys cheaply. It is for developers issuing credentials to their own users or seeding test environments with realistic-looking secrets.

How to use it

1. Type a Prefix or click a preset such as sk_live_, sk_test_, pk_live_, pk_test_, api_ or No prefix. Only letters, digits, underscore, dot and hyphen are kept, up to 24 characters.
2. Drag Random characters between 8 and 128. The label shows the bits of entropy for your choice.
3. Pick an Alphabet: Base62, Hex or Base64url.
4. Set How many, from 1 to 200, and switch on Append checksum suffix if wanted.
5. Select Generate, then use Copy all, Download .txt or the Copy button on a single row.

A test key with a checksum

Prefix sk_test_, Random characters 24, Alphabet Hex, Append checksum suffix on

Format: sk_test_ then 24 hex characters, an underscore, and 6 base36 checksum characters (39 characters in all). Entropy is 96 bits, labeled Strong. The digits are random each time.

When to use it

• Issuing keys for a new developer platform that need a recognizable prefix per environment.
• Creating a batch of test keys to load into a staging database.
• Producing example keys for documentation that look real without being connected to anything.
• Generating a shared secret for a webhook signing setup.

Questions about API key generator

Why put a prefix on a key?

A prefix tells people and secret-scanning tools what kind of key it is and which environment it belongs to, which speeds up spotting and revoking a leak.

What does the checksum suffix do?

It is a 6-character CRC-32 written in base36 after an underscore. Your API can recompute it and reject typos before looking anything up. It is not a signature, since anyone can calculate it.

How long should a key be?

Aim for at least 128 bits of entropy. The default 32 Base62 characters give about 190 bits, and the label moves from Weak below 64 bits through Adequate, Strong, Very strong and Overkill at 256.

Which alphabet gives the most randomness per character?

Base64url carries 6 bits per character, Base62 about 5.95 and Hex 4. Hex is easy to read aloud and to paste into configuration files, while the others are shorter for the same strength.

How should the server store issued keys?

Store only a hash, show the full key to the user once, and be ready to rotate it. Because these keys are high-entropy, a fast hash is adequate.

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