UUID Use Case

UUID as a Primary Key

A UUID primary key lets any node mint a unique row ID without a central counter — ideal for distributed systems and offline-first apps.

Distributed-safeMerge-safePrefer v7

Version

How many

Uppercase Hyphens Braces { }

Result

Generated locally with the Web Crypto API — nothing leaves your browser.

What Is UUID as a Primary Key?

A primary key must be unique and stable. UUIDs satisfy both without a database sequence, so two services can insert rows that never collide even before they sync.
Use v7 for keys: its leading Unix-millisecond timestamp keeps inserts sequential, which keeps B-tree indexes compact. Plain v4 works but scatters inserts across the index.

How to generate

Pick v7 so new rows sort by creation time.
Default the column to a generator (gen_random_uuid() equivalent or app-side v7).
Index it; consider a BRIN index for very large time-ordered tables.

Use Cases

Multi-region databases where a single sequence is a bottleneck.
Offline-first apps that create records before reaching the server.
Public-facing IDs that should not reveal row count or order.

Code Examples

PostgreSQL

CREATE TABLE orders (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v7(),
  total numeric
);

JavaScript

import { v7 as uuidv7 } from 'uuid';
const id = uuidv7(); // time-ordered

Frequently Asked Questions

UUID or BIGSERIAL for a primary key?

UUID scales across nodes and hides volume; BIGSERIAL is smaller and faster but centralised and guessable. Choose UUID when you need distribution or opaque IDs.

Why v7 over v4 for keys?

v7's time prefix makes inserts sequential, avoiding the page splits and fragmentation that random v4 causes in B-tree indexes.

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