UUID Use Case

UUID Shard Key

A shard key decides which partition a row lives on. Random UUIDs distribute writes uniformly; time-ordered ones can pile recent writes onto one shard.

Even spreadv4 recommendedAvoids hotspots

Version

How many

Uppercase Hyphens Braces { }

Result

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

What Is UUID Shard Key?

For sharding you usually want a key with no temporal pattern, so new rows land on every shard instead of accumulating on the 'newest' one.
That is the opposite of the primary-key advice: a random v4 is ideal for the shard key even when the primary key is a v7.

How to generate

Use v4 for the shard/distribution key.
Hash the UUID or use it directly as the partition discriminant.
Monitor per-shard size to confirm an even split.

Use Cases

Multi-tenant storage where tenants must not share a hot shard.
Time-series ingestion fanned out across nodes.
Kafka / queue partitioning by message key.

Code Examples

JavaScript

const id = crypto.randomUUID();

Python

import uuid
id = uuid.uuid4()

Frequently Asked Questions

Why use v4, not v7, for a shard key?

v7's timestamp makes consecutive IDs land on nearby partitions, creating hotspots. v4's randomness spreads load evenly.

Can I shard by a v7 primary key?

You can, but expect recent rows to concentrate on one shard. Keep a separate v4 distribution key if write spread matters.

Related tools

UUID v1 Generator UUID v3 Generator UUID v4 Generator UUID v5 Generator UUID v6 Generator UUID v7 Generator UUID v8 Generator Bulk UUID Generator Short UUID Generator UUID Validator UUID Formatter UUID as a Primary Key UUID Database ID UUID Foreign Key UUID Shard Key UUID Partition Key UUID in a Composite Key UUID Surrogate Key UUID API Key UUID Session Token UUID Access Token UUID Refresh Token UUID Idempotency Key UUID Request ID UUID Correlation ID UUID Trace ID UUID CSRF Token UUID Nonce UUID Filename UUID Object Key UUID S3 Key UUID Upload ID UUID Cache Key UUID Blob Name UUID Temp File UUID User ID UUID Account ID UUID Customer ID UUID Device ID UUID Tenant ID UUID Client ID UUID Anonymous ID UUID Member ID UUID Message ID UUID Event ID UUID Job ID UUID Task ID UUID Queue Message ID UUID Transaction ID UUID Order ID UUID Invoice ID UUID Payment ID UUID Reset Token UUID Verification Token UUID Invite Code UUID API Secret UUID Share Link UUID Magic Link UUID Node ID UUID Worker ID UUID Lock ID UUID Cluster ID UUID Test Data UUID Seed Data UUID Fixture UUID Mock ID UUID Placeholder ID UUID Sample ID