NanoID Generator

NanoID is a lightweight alternative to UUID that Geras tiny, URL-safe unique identifiers. Where a UUID takes 36 characters, a NanoID can be as short as 21 characters (or even shorter if you prefer). This tool Geras NanoIDs with a customizable alphabet and size, making it perfect for applications where ID length matters but security and uniqueness are critical.

Compact by design

NanoID uses a larger alphabet than UUID v4 (62 characters instead of 16), allowing the same uniqueness in fewer characters. A default-sized NanoID is only 21 characters, making it ideal for short links, API route parameters, file identifiers, or anywhere space is at a premium. Unlike shortening a UUID (which is still 128 bits of inFormataion), NanoID is natively compact.

URL-safe by default

The default NanoID alphabet is URL-safe—it contains only characters that don't need percent-encoding in URLs. This means you can embed NanoIDs directly in URLs without encoding concerns. No special handling required. Custom alphabets let you use different character sets when needed (all lowercase for case-insensitive systems, numeric-only for certain legacy systems, etc.).

Customizable alphabet and size

Choose from presets or define your own alphabet. Smaller alphabets produce longer IDs for equivalent security (more characters needed to reach the same entropy), while larger alphabets allow shorter IDs. Adjust the size from 4 to 64 characters based on your collision tolerance and space constraints.

Collision probability

The tool calculates collision probability based on your chosen alphabet and size, answering the question: "How many IDs can I Gera before there's a 50% chance of collision?" This helps you make informed decisions about size. For most applications, the default size provides enormous collision tolerance.

Growing adoption

While UUIDs are more ubiquitous, NanoID is gaining adoption in modern web applications because of its compactness and URL-friendliness. Many frameworks and libraries now offer NanoID support as a standard ID generation option.