UUID vs NanoID — Which Should You Use?
NanoID is shorter and faster. UUID is a universal RFC standard. Here's a practical guide to choosing between them.
What is NanoID?
NanoID is a tiny, zero-dependency ID generator for JavaScript. By default it produces 21-character IDs using an alphabet of A-Z, a-z, 0-9, _, and -:
V1StGXR8_Z5jdHi6B-myT
It is cryptographically secure (uses crypto.getRandomValues()), URL-safe by default, and very popular in the JavaScript ecosystem. The alphabet and size are configurable.
Side-by-Side Comparison
| Property | UUID v4 | NanoID (default) |
|---|---|---|
| Default length | 36 chars (with hyphens) | 21 chars |
| Entropy / randomness | 122 bits | ~126 bits |
| URL-safe without encoding | Yes (hyphens are URL-safe) | Yes |
| Sortable by time | No | No |
| Customizable size/alphabet | No | Yes |
| RFC standard | RFC 4122 / RFC 9562 | No |
| Native database type | PostgreSQL UUID, MySQL 8+ | Needs VARCHAR/TEXT |
| Cross-language stdlib | Python, Java, .NET, Node.js | JS/TS only (ports exist but aren't stdlib) |
| Package size | Zero (native API) | ~120 bytes (tiny npm package) |
| Generation speed | Fast | Slightly faster (smaller output) |
NanoID Quick Example
// npm install nanoid
import { nanoid, customAlphabet } from 'nanoid';
// Default: 21 chars, URL-safe alphabet
const id = nanoid(); // "V1StGXR8_Z5jdHi6B-myT"
// Custom: 10-char numeric ID
const numericId = customAlphabet('1234567890', 10);
numericId(); // "3902841890"
// Custom: 8-char hex ID
const hexId = customAlphabet('0123456789abcdef', 8);
hexId(); // "a7f3c8e2"Decision Guide
Use NanoID when:
- You're building a JavaScript/TypeScript project
- You want shorter IDs (URLs, slugs, user-facing identifiers)
- You need a custom alphabet (e.g. uppercase-only, numeric-only)
- You don't need to store IDs in a UUID-typed database column
Use UUID when:
- You need RFC compliance and cross-language interoperability
- The ID is stored in a
UUIDdatabase column (PostgreSQL, MySQL) - You're working in Python, Java, C#, Go, or other non-JS languages
- Your API or system expects the standard UUID format
- You want sortable IDs — use UUID v7
Frequently Asked Questions
What is NanoID?
NanoID is a tiny, secure, URL-friendly unique ID generator for JavaScript. By default it produces 21-character IDs using an alphabet of A-Z, a-z, 0-9, hyphen, and underscore — e.g. V1StGXR8_Z5jdHi6B-myT. It is cryptographically secure, uses the Web Crypto API, and has no dependencies.
Is NanoID safe to use? Can it collide with UUID?
NanoID (21 chars, default alphabet) has ~126 bits of entropy — comparable to UUID v4's 122 bits. Collision probability is negligible for any realistic application. NanoID and UUID live in separate namespaces and cannot collide with each other.
Should I use NanoID or UUID?
Use NanoID when you need short, URL-safe IDs in JavaScript/TypeScript and don't need to interoperate with UUID-aware systems. Use UUID when you need RFC compatibility, database UUID column support, or cross-language interoperability. For database primary keys, UUID v7 is the better modern choice over both NanoID and UUID v4.