Design ID Systems: Generate UUIDs → Hash → Format as JSON
Design a UUID-based entity ID system: generate bulk UUIDs, hash them for indexed lookup, and format the ID schema as JSON for team documentation.
The Problem
You're designing the ID strategy for a new microservice. Should you use UUIDs or sequential IDs? How do you index UUIDs efficiently? How do you document the ID schema for your team? This workflow walks through each decision with the right tool.
Why This Matters
Choosing the wrong ID strategy early in a project is expensive to fix. UUIDs are globally unique and safe to generate client-side, but they're large and hard to index efficiently. A clear workflow helps you generate examples, understand hash-based optimizations, and document the final schema for your team.
Step-by-Step Instructions
Generate sample UUIDs for your entities
Use the UUID Generator to generate 10-20 example IDs. Copy them as a batch for use in seed data, API documentation, or test fixtures. UUID v4 (random) is the most common choice for distributed systems.
Hash UUIDs for compact indexed lookup
For high-performance lookups, you can store a truncated SHA-256 hash of the UUID as a shorter index key. Paste a UUID into the Hash Generator, compute SHA-256, and take the first 16 characters. This creates a compact, indexed alias.
Document the ID schema as JSON
Paste your entity ID schema definition into the JSON Formatter and format it for team documentation. Include: type, format, generation method, and example values. Well-documented schemas prevent integration mistakes.
Try It Now — UUID Generator
Open full page →All processing happens in your browser — no data is sent to any server.
Before & After Example
# Slack message: 'use UUIDs for user IDs' # Different services implement differently: Service A: '550e8400-e29b-41d4-a716-446655440000' Service B: '550E8400E29B41D4A716446655440000' # no dashes! Service C: 12345 # uses integers instead # Result: integration failures everywhere
{
"id_schema": {
"user_id": {
"type": "string",
"format": "uuid-v4",
"example": "550e8400-e29b-41d4-a716-446655440000",
"generation": "client-side crypto.randomUUID()"
},
"lookup_hash": {
"type": "string",
"format": "sha256-prefix-16",
"example": "550e8400e29b41d4"
}
}
}
Frequently Asked Questions
UUID v4 vs v7 — which should I use?
UUID v4 is random — best for IDs that don't need time ordering. UUID v7 is time-ordered — better for database primary keys because it's monotonically increasing, improving B-tree index performance. For new projects, prefer v7 if your database/language supports it.
Do UUIDs hurt database performance?
Random UUIDs (v4) cause B-tree index fragmentation because inserts are non-sequential. Mitigations: use UUID v7 (time-ordered), use ULID instead, or use a sequential bigint PK with UUID as an alias column. PostgreSQL's uuid type is stored as 16 bytes (compact).
Can I generate UUIDs client-side safely?
Yes, with crypto.randomUUID() in modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+). Node.js has crypto.randomUUID() since v14.17. These use cryptographically secure random number generation — never use Math.random() for IDs.
Related Workflows
Try all 3 tools in this workflow
Each tool is free, runs in your browser, and requires no signup.