UUID Generator

Purpose

Online UUID/GUID generator supporting UUID v1 (timestamp), v3/v5 (namespace-hashed), v4 (random — most common), v7 (sortable, RFC 9562 from 2024). Generates 1-10000 IDs at a time, with dashed/no-dash format and uppercase/lowercase output. GUID is Microsoft's name for the same UUID format. Common for database primary keys, distributed trace IDs, filenames, session tokens, and order numbers. All generation uses crypto.randomUUID.

Steps

1. Pick version: v4 (random, default), v7 (sortable), v1 (with MAC, not recommended), v3/v5 (namespace)
2. Count: 1 / 10 / 100 / 1000 / custom
3. Format: standard 8-4-4-4-12 (with dashes) or compact 32-char (no dashes)
4. Case: lowercase (default) or full uppercase
5. Click Generate for instant output; bulk generation shows progress
6. Copy all or copy individual IDs
7. Export .txt or .csv for database import
8. v3 / v5 require a namespace UUID + name string

FAQ

Should I use UUID v4 or v7?

v4 is fully random — most common, broadest compatibility, but bad as a database primary key (defeats clustered indexes on insert). v7 (RFC 9562, 2024) places a 48-bit ms timestamp in the front and random bits in the rest — UUIDs sort by time naturally, giving near auto-increment performance while staying globally unique. Use v7 for new projects.

Is UUID the same as GUID?

Same thing. GUID (Globally Unique Identifier) is the Microsoft name; UUID (Universally Unique Identifier) is the RFC standard. Format is identical: 8-4-4-4-12 hex chars (32 total). .NET / SQL Server docs say GUID; everyone else says UUID.

Is v4 UUID actually unique? Could it collide?

Theoretically possible, practically negligible. With 122 random bits, ~2.6 billion UUIDs give roughly 50% collision probability. In practice, treat as never-collide — assuming a cryptographically secure source (crypto.getRandomValues / crypto.randomUUID), never Math.random().

UUID v1 contains MAC — privacy issue?

Yes. v1's last 48 bits are the network MAC, leaking which machine generated it. A famous 1998 incident leaked Microsoft internal MAC addresses via Word documents. Modern libs may use random node IDs, but check the implementation. Externally exposed UUIDs: prefer v4 or v7, avoid v1.

What are v3 and v5 for?

Namespace-based deterministic UUIDs. Given the same namespace UUID and name string, they always produce the same UUID. v3 uses MD5, v5 uses SHA-1. Use case: deterministically map external IDs (emails, URLs) to UUIDs without storing a lookup. Prefer v5 (v3 uses MD5, no longer recommended).

Use cases

• Database primary keys: distributed systems cannot use auto-increment IDs; UUID v7 gives better insert performance
• Order or transaction IDs: avoid sequential exposure by using UUIDs for user-visible IDs
• Upload deduplication: rename files to UUID to avoid collisions and hide original names
• Distributed tracing: each request generates a trace_id passed through microservice calls
• Test data: bulk generate 1000 UUIDs to seed a database for perf testing

Use cases

Database primary keys (v7 recommended), order/transaction IDs, file privacy, distributed trace_id, test data. Backend, DBA, QA. v7 sortable output, bulk generation, multi-format export, and namespace UUIDs are the differentiators.