How to Generate NanoIDs
NanoID Generation
When to Use NanoIDs
Use NanoIDs when you need shorter, URL-safe unique strings — short links, client-side temporary IDs, CSS class suffixes, session tokens in cookies, or anywhere UUID length (36 chars) is unnecessarily long.
Real-World Examples
Default 21-char ID: V1StGXR8_Z5jdHi6B-myT — URL-safe alphabet
Short invite codes with custom length (8–12 chars) for share links
React component keys or form field IDs generated on the client
Common Mistakes
- Using very short NanoIDs (under 8 chars) for high-volume systems without assessing collision risk
- Confusing NanoID with UUID — different alphabet, length, and entropy model
- Storing NanoIDs case-sensitively when the alphabet includes both upper and lower case
Edge Cases
- Default size 21 with 64-char alphabet gives ~126 bits of entropy — comparable to UUID v4
- Custom alphabets change collision probability — document your size choice
- Hyphen and underscore in default alphabet are URL-safe but may need encoding in some legacy systems
Developer Tips
- npm:
import { nanoid } from 'nanoid'— battle-tested reference implementation - Increase size for higher collision resistance: each extra char adds ~6 bits with the default alphabet
- Use ULIDs or UUIDs when you need standard formats for database interoperability
Frequently asked questions
What is the default NanoID length?
This tool generates 21-character NanoIDs by default when the input is empty — matching the nanoid library default, which provides UUID-comparable collision resistance.
How do I generate a custom size or batch?
Enter a size (1–64) for one ID, a count (1–50) for multiple default-length IDs, or "count, size" (e.g. "5, 12") for batch custom-length IDs.
Is NanoID better than UUID?
NanoIDs are shorter and URL-safe by default. UUIDs are more universally recognized in databases and APIs. Choose based on length constraints and ecosystem expectations.