UUID v4, v7, ULID, or NanoID — Which Should You Use?

If you're looking for a uuid generator online, chances are you just need a quick UUID. But there are actually a few flavours to choose from, and picking the right one can save you headaches later. Here's the short version: UUID v7 for databases, NanoID for short tokens, UUID v4 when you need to play it safe. The UUID Generator on SnipKit covers all three.

Quick Comparison

UUID v4 — The Safe Default

UUID v4 is what most people mean when they say "UUID" or "GUID". Every language, framework, and database supports it out of the box. It looks like this: 550e8400-e29b-41d4-a716-446655440000.

The catch: it's completely random, so new IDs land in unpredictable places in the database index. That's fine for small projects. For high-traffic apps with millions of writes, it starts to slow things down.

UUID v7 — The Better UUID

UUID v7 looks identical to v4 — same format, same length, works in the same columns. The difference is that it starts with a timestamp, so new IDs always come after old ones. That makes your database much happier at scale: inserts are faster and the index stays tidy.

It's supported in most modern ORMs (Prisma, Drizzle, Hibernate) and is the easiest upgrade you'll ever make. UUID v7 also makes ULID mostly redundant — it gives you the same sortability in a format the whole ecosystem already knows. Any decent uuid generator online should let you generate v7.

Use it when: you're designing a new schema and want better database performance without changing anything else.

ULID — Sortable, But Niche

ULID looks different: 01ARZ3NDEKTSV4RRFFQ69G5FAV. It's shorter, URL-safe, and sorts chronologically just like UUID v7. One thing most articles don't mention: in "monotonic mode", ULIDs generated within the same millisecond still sort correctly — useful for event logs where order really matters.

The downside is ecosystem support. ULID is a community standard, not an official spec, so some databases and ORMs don't have native support. If you're starting fresh, UUID v7 is the better choice. If your codebase already uses ULIDs, there's no rush to migrate.

Use it when: you're already using it, or you specifically need Base32 IDs in logs.

NanoID — For Tokens, Not Tables

NanoID generates short, URL-safe strings like V1StGXR8_Z5jdHi6B-myT. At the default length of 21 characters it's as collision-resistant as UUID v4, but much more compact. It's cryptographically secure and tiny — under 120 bytes in the browser.

The important thing to know: NanoID has no timestamp, so IDs don't sort by time. That makes it a poor choice as a database primary key. It's perfect for session tokens, URL slugs, invite codes, and anything where you want a short, random, URL-safe string. For actual passwords and secrets, use a proper password generator — NanoID is for IDs, not credentials.

Use it when: you need a compact, URL-safe identifier on the frontend or for short-lived tokens.

Which One to Pick

• Starting a new project? Use UUID v7 for your database IDs.
• Need short, URL-safe tokens? Use NanoID.
• Integrating with legacy systems? Stick with UUID v4.
• Already using ULID? Keep it — but choose UUID v7 for new tables.
• Working with encoded data? The Base64 Encoder/Decoder can help with format conversions.

FAQ

Is UUID the same as GUID?

Yes. GUID is just Microsoft's name for UUID. Same format, same idea — the terms are used interchangeably.

How likely is a UUID v4 collision?

Practically impossible. You'd need to generate over 100 trillion UUIDs before there's even a one-in-a-billion chance of a duplicate. Don't worry about it.

Is NanoID more secure than UUID?

They're comparable — both use a cryptographically secure random generator. Neither is meant to be a secret by itself. If you need an actual secret, use a password generator.

Generate Your IDs

Try the free uuid generator online — supports UUID v4, v7, and bulk generation. No signup, no install.