UUID Generator Online — Generate Unique IDs Instantly
Every database record, every API resource, every test fixture needs a unique identifier. You could write code to generate one — or you could paste it from a generator in five seconds.
The UUID Generator creates version 4 UUIDs instantly. Generate one, generate ten, copy and use.
What Is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as a 32-character hexadecimal string split into five groups:
550e8400-e29b-41d4-a716-446655440000
Version 4 UUIDs are randomly generated — the probability of generating the same UUID twice is astronomically low. That's what makes them safe to use as unique identifiers without a central registry or database check.
Where Developers Use UUIDs
Database primary keys — instead of auto-incrementing integers, UUIDs as primary keys are safer for distributed systems, harder to enumerate, and work across multiple databases without conflicts.
API resource IDs — exposing sequential IDs in your API (/users/1, /users/2) lets anyone enumerate your data. UUIDs like /users/550e8400-e29b-41d4-a716-446655440000 give nothing away.
Firebase and Firestore — Firestore document IDs are UUID-like strings. Generating your own UUID before creating a document lets you know the ID before the write completes.
Flutter app development — when building offline-first Flutter apps, you need to generate IDs on the device before syncing to a backend. UUIDs are the standard approach.
Test data and fixtures — writing tests that need unique IDs without hitting a database? Generate UUIDs here and hardcode them in your test fixtures.
Session and transaction IDs — tracking user sessions, payment transactions, and audit logs with UUIDs makes them globally unique and safe to log.
How to Use the UUID Generator
- Go to rohansurve.in/free-tools/uuid-generator
- Click generate
- Copy the UUID
- Generate as many as you need
Runs entirely in your browser. Nothing sent to a server.
UUID vs ULID vs NanoID — Which Should You Use?
UUID v4 — purely random, universally supported, the safe default choice for most use cases.
UUID v7 — newer standard, time-ordered (sortable), better for database indexing performance. Worth considering for new projects.
ULID — time-ordered like v7, URL-safe, slightly shorter. Popular in modern backends.
NanoID — shorter than UUID, URL-safe, customisable length. Good for user-facing IDs where shorter is better.
For most projects, UUID v4 is the right choice. It's supported everywhere, well understood, and the generator here produces them instantly.
Related Developer Tools
- MD5 Generator — generate MD5 hashes for checksums
- Password Generator — generate strong random passwords
- Base64 Encoder — encode strings and data in Base64
- Timestamp Converter — convert Unix timestamps to readable dates
- JSON Formatter — format JSON responses and data
All free at rohansurve.in/free-tools.
Generate One Right Now
Stop writing throwaway code to generate IDs during development. The UUID Generator is faster — open, click, copy, done.
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