UUID v7: The Time-Based Identifier You Should Be Using

UUID v7 is a new UUID format defined in RFC 9562 that combines the best properties of UUIDs with time-based ordering. It is rapidly becoming the recommended choice for primary keys in databases.

Why UUID v7 Over v4?

UUID v4 is purely random, which causes several problems in practice:

• Poor database index performance: Random UUIDs cause excessive B-tree page splits
• No natural ordering: You cannot sort by creation time without an additional column
• Cache unfriendly: Random distribution means poor locality of reference

UUID v7 solves all of these by embedding a Unix timestamp in the first 48 bits.

Generating UUID v7

// Using the uuid package (v9+)

import { v7 as uuidv7 } from 'uuid';
const id = uuidv7();
// "018ec3e2-7c5a-7d1e-8b3f-4a5c6d7e8f9a"

Database Performance Benefits

Benchmarks consistently show UUID v7 outperforming UUID v4 for indexed columns:

MetricUUID v4UUID v7Improvement

|--------|---------|---------|-------------|

Insert rate12K/s45K/s3.75x Index size (1M rows)89 MB64 MB28% smaller Range query45ms8ms5.6x faster

The time-based ordering means new records are always appended to the end of the B-tree index, eliminating random page splits.

Migration Strategy

Moving from UUID v4 to v7 is straightforward since they share the same 128-bit format. Existing v4 UUIDs remain valid — simply start generating v7 for new records.

Use our UUID Generator tool to create UUID v7 identifiers instantly.