UUID Alternatives: ULID, NanoID, CUID, and Short UUID Compared

Meta Description: Compare UUID alternatives like ULID, NanoID, CUID, and short UUID. Find the best unique identifier format for your use case with this complete comparison guide.

UUIDs work great. But 36 characters is a lot for a URL. And random v4 UUIDs don't sort. And sometimes you need something more readable.

Enter the alternatives: ULID, NanoID, CUID, and short UUID formats. Each solves specific problems UUIDs don't. Here's how to choose.

Why Look Beyond UUID?

UUIDs have real limitations:

These alternatives address one or more of these issues.

ULID: Universally Unique Lexicographically Sortable Identifier

What Is It?

ULID = Timestamp (48 bits) + Randomness (80 bits)

01ARZ3NDEKTSV4RRFFQ69G5FAV
├─────────┤├────────────────┤
timestamp      randomness
  (10)           (16)

Key Features

ULID vs UUID

When to Use ULID

• ✅ Need sortable IDs
• ✅ URLs or user-facing IDs
• ✅ Database primary keys
• ✅ Distributed systems
• ❌ Need maximum entropy (use UUID v4)

Generate ULID

// JavaScript
import { ulid } from 'ulid';
const id = ulid();
// 01ARZ3NDEKTSV4RRFFQ69G5FAV

# Python
import ulid
id = ulid.new()
print(id.str)
# 01ARZ3NDEKTSV4RRFFQ69G5FAV

→ ULID Generator

NanoID: Compact, Fast, URL-Safe

What Is It?

NanoID is a tiny (130 bytes), fast, URL-friendly unique ID generator.

V1StGXR8_Z5jdHi6B-myT

Key Features

NanoID vs UUID

When to Use NanoID

• ✅ Frontend-generated IDs
• ✅ URLs and slugs
• ✅ Need small bundle size
• ✅ Custom alphabet requirements
• ❌ Need timestamp/sortability

Generate NanoID

// JavaScript
import { nanoid } from 'nanoid';
const id = nanoid();
// V1StGXR8_Z5jdHi6B-myT

// Custom length
const short = nanoid(10);
// IRFa-VaY2b

// Custom alphabet
import { customAlphabet } from 'nanoid';
const numbers = customAlphabet('1234567890', 12);
numbers();
// 374185294637

# Python
from nanoid import generate
id = generate()
# V1StGXR8_Z5jdHi6B-myT

CUID / CUID2: Collision-Resistant IDs

What Is It?

CUID (Collision-resistant Unique Identifier) is designed for horizontal scaling without coordination.

CUID (v1):

ch72gsb320000udocl363eofy

CUID2 (recommended):

tz4a98xxat96iws9zmbrgj3a

Key Features

CUID vs UUID

When to Use CUID

• ✅ Distributed systems without coordination
• ✅ Security-sensitive applications
• ✅ Need lowercase-only IDs
• ✅ Horizontal scaling
• ❌ Need strict time ordering

Generate CUID

// JavaScript
import { createId } from '@paralleldrive/cuid2';
const id = createId();
// tz4a98xxat96iws9zmbrgj3a

# Python
from cuid2 import cuid_wrapper
cuid_generator = cuid_wrapper()
id = cuid_generator()
# tz4a98xxat96iws9zmbrgj3a

Short UUID: Human-Readable UUIDs

What Is It?

Short UUID encodes standard UUIDs in a more compact format.

Standard UUID:

f47ac10b-58cc-4372-a567-0e02b2c3d479

Short UUID (Base57):

mhvXdrZT4jP5T8vBxuvm75

Key Features

When to Use Short UUID

• ✅ Need UUID compatibility but shorter format
• ✅ Existing UUID infrastructure
• ✅ Human-readable URLs
• ✅ QR codes (less data = faster scanning)

Generate Short UUID

// JavaScript
import short from 'short-uuid';
const translator = short();

// Generate
const shortId = translator.new();
// mhvXdrZT4jP5T8vBxuvm75

// Convert existing UUID
const fromUuid = translator.fromUUID('f47ac10b-58cc-4372-a567-0e02b2c3d479');
// mhvXdrZT4jP5T8vBxuvm75

// Convert back
const uuid = translator.toUUID(shortId);
// f47ac10b-58cc-4372-a567-0e02b2c3d479

Complete Comparison Table

Decision Matrix

Choose UUID v4 When:

• Maximum compatibility required
• Standard libraries only
• Entropy is critical
• Not concerned about length

Choose ULID When:

• Need sortable IDs
• Database primary keys
• Time-series data
• 26 characters acceptable

Choose NanoID When:

• Shortest possible IDs
• Custom alphabets needed
• Frontend generation
• Bundle size matters

Choose CUID2 When:

• Distributed systems
• Security-first applications
• Lowercase-only requirement
• Need fingerprinting

Choose Short UUID When:

• Must maintain UUID compatibility
• Existing UUID infrastructure
• Need reversible encoding
• URLs with UUIDs

Generate Any Format

Use our generators:

• UUID Generator — Classic v4, v7 UUIDs
• ULID Generator — Sortable, 26-character IDs
• NanoID Generator — Compact, customizable IDs

FAQ

Which has the lowest collision probability?

UUID v4 and NanoID (21 chars) have ~126 bits of entropy. ULID has 80 bits random (timestamp adds uniqueness). All are effectively collision-proof for practical use.

Can I use these in databases?

Yes. ULID and CUID2 are specifically designed for database use. NanoID works but doesn't optimize for sorted inserts. Store as VARCHAR or TEXT.

Are these compatible with each other?

No. Each format is distinct. Short UUID is special—it encodes/decodes regular UUIDs, so it's UUID-compatible.

Which is best for URLs?

NanoID (shortest) or ULID (sortable). Both are URL-safe. CUID2 is lowercase, good for case-insensitive URLs.

Can I migrate from UUID to ULID?

Not directly—they're different formats. You'd need to:

1. Add new ULID column
2. Generate ULIDs for existing rows
3. Update references
4. Drop UUID column

Or maintain both columns during transition.

Related Tools:

• UUID Generator — Classic UUID generation
• ULID Generator — Sortable IDs
• NanoID Generator — Compact IDs