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A UUID (Universally Unique Identifier) is a 128-bit value virtually guaranteed to be unique across systems, making it useful anywhere you need an identifier without coordinating with a central database to avoid collisions — database primary keys, request IDs, session tokens, and more. This tool generates random version-4 UUIDs (the most common variant, based on random bits rather than a timestamp or hardware address), one at a time or in bulk.
You can generate up to 100 at once, and optionally strip the hyphens or uppercase the output to match whatever format your system expects.
How it works
Choose how many UUIDs you need (up to 100), and whether you want hyphens included and the letters uppercased. Click generate and every UUID appears instantly, ready to copy.
- Choose how many UUIDs you need.
- Optionally toggle uppercase or remove hyphens.
- Generate and copy the results.
Examples
A single database primary key
Generating one UUID like "a1b2c3d4-e5f6-4789-a012-3456789abcde" gives a unique identifier that can be assigned without checking against existing keys.
Bulk-generating test data
Generating 50 UUIDs at once quickly provides unique identifiers for seeding test records or fixtures.
Who should use it
- Generating unique database primary keys or record identifiers.
- Creating request IDs, session tokens, or trace identifiers.
- Bulk-generating unique identifiers for test data or fixtures.
Industry applications
- Software development and database design
- API development and distributed systems
- QA and test data generation
Advantages
- Generates up to 100 UUIDs at once.
- Optional uppercase and no-hyphen formatting to match different system conventions.
- No account or software installation needed.
Limitations
- Only generates version-4 (random) UUIDs, not version 1, 5, or 7 variants.
- Not human-readable or memorable — not suitable for customer-facing reference numbers.
Common mistakes to avoid
- Assuming a UUID needs to be checked against a database for uniqueness before use — the collision probability is negligible enough that this isn't necessary in practice.
- Using a UUID where a shorter, more memorable identifier would serve users better (like an order number shown to a customer).
- Mixing UUID formats (with/without hyphens, upper/lowercase) inconsistently across a system.
Best practices
- Use UUIDs for identifiers that don't need to be human-readable or memorable, and a separate short reference number for anything customer-facing.
- Keep a consistent format (hyphenated, lowercase is the most common convention) across your entire system.
- Prefer version-4 UUIDs for general-purpose unique identifiers unless you specifically need timestamp ordering (version 1/7) or deterministic generation from a name (version 5).
Tips
- If your database column has a fixed UUID format expectation (with/without hyphens), check that before bulk-generating and importing many at once.
- For identifiers that need to sort chronologically, look into version-7 UUIDs or ULIDs instead of version-4, which are purely random.