UUID Generator — Free Online Tool

A UUID generator creates universally unique identifiers (UUIDs) that can be used as database primary keys, API request IDs, distributed tracing tokens, and test fixtures. SWEDevTools: Prism offers a free, browser-based UUID generator supporting both UUID v4 (random) and UUID v7 (time-ordered), with bulk generation and multiple output formats—all processed locally with no server interaction.

Features

• UUID v4 and v7 support: Generate random UUIDs (v4) or time-ordered UUIDs (v7) without installing CLI tools or adding library dependencies.
• Multiple output formats: Output in standard, uppercase, no-dashes, or {braced} formats to match APIs, legacy systems, and database conventions.
• Bulk generation: Generate multiple UUIDs at once for test fixtures, seed scripts, demo datasets, and migration files.
• Works offline as a PWA: Install SWEDevTools: Prism and generate UUIDs without an internet connection—useful for air-gapped development environments.
• No signup required: Generate UUIDs instantly with zero account creation, no email verification, and no usage limits.
• Local-first processing: All UUIDs are generated in your browser using the Web Crypto API. No data is sent to any server.
• Pipeline chaining support: Chain generated UUIDs into other tools for JSON wrapping, hashing, or embedding in config file templates.

Frequently Asked Questions

Is the UUID generator free?

Yes, the SWEDevTools: Prism UUID generator is completely free with no signup, no ads, and no usage limits.

Does the UUID generator work offline?

Yes. SWEDevTools: Prism is a PWA that works without an internet connection once installed on your device.

Is my data safe?

Yes. UUIDs are generated locally in your browser using the Web Crypto API. No data is sent to any server.

What is the difference between UUID v4 and v7?

UUID v4 is fully random. UUID v7 embeds a timestamp prefix followed by random bits, producing roughly time-ordered IDs that improve B-tree index locality in databases while still being globally unique.

Are UUIDs guaranteed to be unique?

No finite system can guarantee absolute uniqueness, but the probability of a UUID v4 collision is astronomically low (1 in 2^122). Always enforce uniqueness constraints at the database layer as a safety net.

Can I use UUIDs as database primary keys?

Yes, UUIDs are commonly used as primary keys. Consider UUID v7 for better index performance compared to fully random v4 IDs, which can cause index fragmentation in B-tree databases.

Is UUID v4 cryptographically secure?

UUID v4 uses random bits, but UUIDs are identifiers, not security tokens. For authentication tokens or secrets, use purpose-built token formats with proper entropy and secure storage.

What is the difference between GUID and UUID?

GUID (Globally Unique Identifier) is Microsoft's term for the same 128-bit identifier format. In practice, GUIDs and UUIDs are interchangeable and follow the same RFC 9562 specification.

Why would I use the no-dashes format?

Some systems store UUIDs as 32 hex characters without hyphens for compactness—common in legacy database schemas, URL-safe identifiers, and configuration files where dashes may cause parsing issues.

How many UUIDs can I generate at once?

The tool supports bulk generation of many UUIDs at once, output as newline-separated values for easy copy-paste into seed scripts, fixtures, and migration files.

Is Prism a good alternative to uuidgenerator.net?

Yes. SWEDevTools: Prism generates UUIDs locally in your browser using the Web Crypto API, while uuidgenerator.net generates them server-side. Prism also supports UUID v7 (time-ordered), multiple output formats, bulk generation, works offline as a PWA, and lets you chain UUIDs into other tools in a pipeline.

What happened to smalldev.tools?

smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.