UUID Generator
Generate and copy UUID v4 values instantly in your browser. Supports batch generation, uppercase output, and compact no-hyphen format.
You can generate up to 50 UUIDs at once.
Hyphenated UUIDs are 36 characters. Compact UUIDs are 32 characters.
How to use this UUID generator
A UUID (Universally Unique Identifier) is a string designed to be unique across systems with an extremely low collision probability. This free UUID generator helps you create one or many UUIDs quickly for development, QA, logging, and prototyping.
Generated in your browser
Everything happens locally in your browser with no server upload. Great for mock data, request IDs, and quick development workflows.
Standard UUID v4 format
Uses the RFC 4122 random UUID v4 format, commonly used for database keys, request tracing, and unique resource identifiers.
Built for practical workflows
Useful for API request IDs, sample database rows, event tracking keys, test fixtures, and frontend temporary identifiers.
Why teams rely on UUIDs
- They can be generated independently across distributed systems with a very low collision risk.
- You do not need a central sequence server or shared auto-increment counter to issue IDs.
- They work well for APIs, events, async jobs, trace IDs, and frontend-generated temporary identifiers.
- Because generation can happen directly in the browser, UUIDs are convenient for test fixtures, mock data, and admin tooling.
Common use cases
- Create unique test IDs in bulk for staging or QA environments
- Generate request IDs for API debugging and log correlation
- Prepare sample database keys for demos and mock datasets
- Assign distinct identifiers to jobs, events, and background tasks
How UUID versions differ
UUID v1
Time-based and partially device-based. It has ordering benefits, but it can expose generation timing and machine information, so it needs careful evaluation.
UUID v4
Random-based and the most widely used option. It is simple, portable, and a strong default choice for many frontend and backend workflows.
UUID v7
A newer time-ordered UUID design. It keeps rough creation order while staying distributed-system friendly, making it attractive for database indexing strategies.
Understanding UUID structure
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A standard UUID string has 36 characters including hyphens, split into five groups. Remove the hyphens and the same value becomes a 32-character compact string.
Version bits
The first character of the third group indicates the UUID version. For UUID v4, this position is typically the number 4.
Variant bits
The first character of the fourth group carries the variant. In common RFC 4122 UUIDs, it is usually one of 8, 9, a, or b.
Recommended best practices
- Compact no-hyphen output is often easier to use inside filenames, query params, or shorter UI layouts.
- If index locality matters in a large database, consider time-sortable alternatives such as ULID or UUID v7 alongside UUID v4.
- Uppercase vs lowercase is usually cosmetic, but legacy systems sometimes enforce uppercase formatting.
- Identifiers and security tokens are different concerns. Avoid using plain UUIDs alone as authentication secrets.
UUID vs other identifier strategies
- Auto-increment numeric IDs are short and fast, but they require centralized coordination and are easy to guess when exposed externally.
- UUID v4 is highly portable and easy to generate in distributed systems, though its randomness can reduce index locality in some databases.
- ULID and UUID v7 offer stronger time ordering, so they are often evaluated for logs, analytics events, and append-heavy storage workloads.