UUID & ULID Generator (v1, v4, v7) – Free Online Tool
Generate UUIDs instantly with our free online UUID generator. Create UUID v4 (random), v1 (time-based), v7 (sortable), and ULIDs for modern applications. Perfect for developers working with databases, APIs, and distributed systems.
Recent Batches
No history yet...
Deep Dive into UUIDs
A UUID (Universally Unique Identifier) is a 128-bit number used to identify information in computer systems. Centrigon's Pro Toolkit supports multiple standards used by developers worldwide.
Version 4 (Random)
The standard for 99% of web applications. It relies on cryptographically secure random numbers. With $2^{122}$ possible combinations, collisions are statistically impossible in our lifetime.
Version 1 (Time)
v1 UUIDs use the current time (with 100ns precision) and a "node" identifier. This allows database records to be naturally sorted by time without an auto-incrementing integer.
Version 7 (Next-Gen)
The new "future-proof" UUID. It combines a 48-bit timestamp with random data. v7 is naturally sortable, significantly improving database indexing performance over v4.
ULID
128-bit sortable identifiers using Crockford's Base32. They are case-insensitive and maintain lexicographical sorting, perfect for distributed systems where readability matters.
How to Generate a UUID
- Select the UUID version (v4, v1, v7, or ULID)
- Choose how many IDs you want to generate
- Click the Generate button
- Copy or download your UUIDs instantly
This free UUID generator works directly in your browser. No signup required, and your data never leaves your device.
When to Use Each UUID Version
- UUID v4 (Random): Best for most applications. Use when you need secure, unpredictable identifiers.
- UUID v1 (Time-based): Useful when you need chronological ordering based on generation time.
- UUID v7 (Modern): Recommended for databases. Combines timestamp ordering with randomness for better indexing performance.
- ULID: Ideal when you need readable, sortable IDs for distributed systems or logs.
Frequently Asked Questions
What is a UUID generator?
A UUID generator creates universally unique identifiers used in software development to uniquely identify data across systems.
How do I generate a UUID online?
Select a UUID version, choose the quantity, and click generate. You can instantly copy or download the results.
What is the difference between UUID v4 and v7?
UUID v4 is completely random, while UUID v7 includes a timestamp, making it sortable and better for database indexing.
Can I generate UUIDs without hyphens?
Yes, you can disable hyphens using the toggle option in the generator settings.
Is this UUID generator secure?
Yes. All UUIDs are generated locally in your browser. No data is sent to any server.
What is a ULID?
A ULID is a sortable, human-friendly identifier similar to UUID, commonly used in distributed systems.
Local history is stored securely in your browser's local storage. Your generated identifiers never leave your machine.