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UUID Generator Online

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Generated UUIDs

98c7af5e-1430-4916-bfd5-36f882ef5c79

About the UUID

Generate UUIDs online - free, private, and instant. This tool creates random UUID v4 identifiers (plus v1) for database keys, API request IDs, and distributed systems, in single or batch mode, all generated locally in your browser.

A UUID (Universally Unique Identifier) is a 128-bit identifier that is unique across systems without any coordinating authority. Version 4 UUIDs use random values and are the default choice for database primary keys, distributed system IDs, API request tracing, and file names where collisions are unacceptable.

Generate single UUIDs or batches in one click. Everything happens locally with the browser crypto API — statistically you would need to generate billions of UUIDs before seeing a duplicate.

Use cases and examples

Generate primary keys before an insert so client code can reference rows it is about to create - essential in offline-first apps and event-driven architectures.

Create correlation IDs for API requests and log lines so a single trace ID ties a user action across services.

Produce fixture data for tests: batch-generate hundreds of UUIDs and paste them directly into seed files or test scripts.

How to use

  1. Choose the UUID version you need (v4 for random IDs, v1 for time-based).
  2. Set the quantity to generate one or hundreds at once.
  3. Click Generate — results appear instantly.
  4. Copy individual UUIDs or the whole batch to your clipboard.

Frequently Asked Questions

What UUID versions are supported? ▾

The Formatho UUID generator supports UUID v1 (timestamp-based), v4 (random), v5 (namespace + SHA-1), and v7 (timestamp + random). All generated locally in your browser.

Are generated UUIDs unique? ▾

Yes. UUID v4 uses 122 bits of randomness making collisions astronomically unlikely. UUID v1 combines timestamp with MAC address for uniqueness.

Are UUIDs generated in the browser safe for production use? ▾

Yes — v4 UUIDs here use the browser's crypto.getRandomValues(), a cryptographically secure random source. They are as unpredictable as any server-generated UUID, and generating them locally means your seeding data never touches a network.

What is the difference between UUID v1 and v4? ▾

v1 encodes a timestamp and the generating machine's MAC address (privacy and collision concerns); v4 is 122 random bits. v4 is the modern default; use ULIDs or UUIDv7 when you need sortability.

Can I generate UUIDs in bulk? ▾

Yes — generate thousands at once for test fixtures and database seeds. Bulk generation happens locally, so large batches are instant and private.