UUIDs are reliable but long and visually clunky in a URL. NanoID was built specifically to be smaller, faster to generate, and friendlier to look at — this tool generates them.
A modern, minimalist answer to "we don't need 36 characters"
NanoID was created by developer Andrey Sitnik and released as an open-source JavaScript library, explicitly designed around the observation that standard UUIDs, at 36 characters including hyphens, are often longer than necessary for many practical use cases — particularly URL-facing identifiers like short links or public resource IDs, where compactness and readability genuinely matter. NanoID achieves comparable collision resistance to a UUID in a much shorter string by using a larger, URL-safe character alphabet (64 possible characters per position, versus hexadecimal's 16), packing more entropy into fewer characters.
How this tool generates a NanoID
The tool generates a string of cryptographically random characters (typically 21 by default, matching the original NanoID specification's chosen length for comparable collision resistance to a UUID v4) drawn from a URL-safe alphabet of uppercase and lowercase letters, digits, and two additional symbols (underscore and hyphen) — carefully chosen so the resulting ID can be used directly in a URL path without any escaping or encoding required.
Where NanoIDs are a genuinely good fit
- Short URLs and public-facing resource identifiers — link shorteners, shareable document IDs and public API resource paths benefit from NanoID's shorter, URL-safe format compared to a bulkier UUID.
- Client-side ID generation in JavaScript applications — NanoID's small library footprint and fast generation speed made it especially popular in front-end and Node.js applications needing to generate unique IDs without heavy dependencies.
- React and component key generation — generating unique keys for dynamically created UI elements or temporary client-side identifiers before a record is saved to a database.
- Session tokens and temporary identifiers — any scenario needing a reasonably short, hard-to-guess random string without the visual overhead of a full UUID's hyphenated hexadecimal format.
Frequently asked questions
Is a 21-character NanoID as collision-resistant as a 36-character UUID? Very close — NanoID's larger alphabet (64 characters versus hex's 16) means each character carries more entropy, so a 21-character NanoID achieves a collision probability comparable to a standard UUID v4 despite being noticeably shorter.
Can I choose a custom length or alphabet? Yes, in most NanoID implementations — unlike UUID, which follows a fixed, standardized format, NanoID's design explicitly allows customizing both the ID length and the character set for specific needs, such as using only digits for a numeric-looking ID or shortening length for less critical use cases.
Why choose NanoID over UUID for a new project? Primarily for URL and display aesthetics, plus a smaller code footprint if you're specifically working in JavaScript — functionally, both provide strong collision resistance, so the choice mostly comes down to whether shorter, URL-friendly IDs matter more to your use case than UUID's status as a long-standing, universally recognized standard.
Further reading
NanoID GitHub repository — The original open-source project and technical documentation for NanoID.
Wikipedia — UUID — The standard identifier format NanoID offers a shorter, URL-friendly alternative to.