Nano ID
Tiny, secure URL-friendly unique ID generator. Nano ID generates cryptographically strong random IDs using the `crypto` module (Node.js) or `crypto.getRandomValues` (browser). Default alphabet uses URL-safe characters (A-Za-z0-9_-), producing shorter IDs than UUIDs for the same collision probability. 21 characters by default. Replaces uuid v4 for most use cases — 40% smaller IDs with same randomness guarantees.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Uses cryptographically secure random (crypto module/crypto.getRandomValues). Zero dependencies. MIT licensed. Not suitable for cryptographic key material — use dedicated crypto libraries for keys.
⚡ Reliability
Best When
You need short, URL-safe, cryptographically secure random IDs for resources, sessions, or tokens — Nano ID is the modern replacement for UUID v4.
Avoid When
You need sortable IDs (use ULID/UUIDv7), require standard UUID format, or need database-optimized sequential IDs.
Use Cases
- • Generate unique IDs for agent-created resources, sessions, and correlation IDs with URL-safe characters
- • Create shorter, more readable IDs for user-facing URLs and permalinks compared to UUID v4
- • Generate cryptographically secure random tokens for one-time links, invitation codes, and nonces
- • Create collision-resistant IDs in distributed agent systems without central coordination
- • Use as drop-in UUID replacement with 40% shorter IDs and URL-safe alphabet
Not For
- • Time-sortable IDs — use ULID or UUIDv7 when chronological ordering matters
- • UUIDs required by spec — some systems require UUID format specifically; use the uuid library then
- • Extremely high collision-sensitivity — for financial transaction IDs, use UUIDs v7 with proven entropy analysis
Interface
Authentication
No authentication — local ID generation.
Pricing
MIT-licensed open source. ~130 bytes minzipped.
Agent Metadata
Known Gotchas
- ⚠ Nano ID v4 is ESM-only — CommonJS require('nanoid') no longer works; use import { nanoid } from 'nanoid' or stay on v3 for CommonJS
- ⚠ Custom alphabet reduces character space — smaller alphabets require longer IDs for same collision probability; use the Nano ID collision calculator to verify your size/alphabet combination
- ⚠ IDs are not time-sortable — if you need to sort by creation time, use ULID or store creation timestamp separately
- ⚠ nanoid() is async-friendly but synchronous — no need to await; nanoid() returns a string directly
- ⚠ Default size of 21 characters is tuned for 1% probability of collision in 1 trillion IDs — increase size for higher collision resistance
- ⚠ Nano ID uses URL-safe alphabet by default — includes underscore and hyphen; if your use case requires alphanumeric only, specify custom alphabet
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Nano ID.
Scores are editorial opinions as of 2026-03-06.