What is NanoID?
NanoID is a tiny, secure, URL-safe string ID generator for JavaScript. It has rapidly grown to become the premier modern alternative to UUID in web development. By using a larger alphabet than standard hexadecimal UUIDs (64 characters vs 16 characters), NanoID can pack the exact same cryptographic entropy into significantly fewer characters.
NanoID vs UUID
While UUIDv4 generates a 36-character string (including hyphens), the standard NanoID generates a compact 21-character string. From a mathematical perspective, both provide exactly the same probability of collision.
- Size: NanoID is vastly smaller in source code size compared to legacy UUID libraries.
- URL-Safe: NanoIDs use
A-Za-z0-9_-, making them natively URL-safe. They are perfect for public URLs like YouTube or Notion links. - Customizable: Unlike UUIDs which strictly mandate the format
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxand only allow hexadecimal characters, NanoID allows developers to define a custom length and a custom alphabet to perfectly match their system's requirements.
How to Generate Custom NanoIDs
- Choose your desired ID length using the slider. The default is 21 characters, which is mathematically equivalent to UUIDv4 collision resistance.
- Select your alphabet from the dropdown. You can use standard URL-safe characters, hexadecimal, numbers only, or type your own custom alphabet.
- Review the Collision Calculator to ensure your chosen length and alphabet provide enough entropy for your generation speed.
- Enter the quantity of IDs you want to generate (up to 10,000) and click Generate NanoIDs.
Frequently Asked Questions
What is the difference between NanoID and UUID?
NanoID is smaller, faster, and URL-safe by default compared to standard UUIDs. While a UUID requires 36 characters to display its 128 bits of entropy, NanoID uses a larger 64-character alphabet to pack the exact same collision resistance into just 21 characters.
Are NanoIDs cryptographically secure?
Yes. NanoID relies on the browser's native Web Crypto API (crypto.getRandomValues())
to generate unguessable, cryptographically strong random values. It does not use the insecure
Math.random().
How does the Collision Calculator work?
The built-in collision calculator uses the formula n ≈ sqrt(0.02 * N) (where N is
the total number of combinations possible given your alphabet and length) to estimate how long
it would take to reach a 1% probability of generating two identical IDs.