Use this free UUID generator to create random, universally unique identifiers (UUID v4) instantly. UUIDs are used by developers as database primary keys, session tokens, API keys and file names where a globally unique identifier is required.
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as a string of 32 hexadecimal characters separated by hyphens. They're used in software development to assign a unique ID to database records, API requests, session tokens, and other objects where uniqueness across systems is critical.
If you need a UUID for testing, prototyping, seeding a database, or generating a placeholder ID in your code, this tool generates one instantly. Click generate and copy — no setup required.
Step 1 — Click generate. The tool generates a cryptographically random UUID v4 (the most commonly used version) instantly. Each click produces a different ID.
Step 2 — Copy the UUID. Click the copy button or select and copy manually. The UUID is ready to paste directly into your code, database, API request, or anywhere else you need it.
Step 3 — Generate in bulk if needed. If you need multiple UUIDs — for seeding test data, for example — generate them one at a time and paste each one. Most developers generate several at once when setting up test data.
Using the same UUID twice. The whole point of a UUID is uniqueness. If you copy the same UUID and use it in multiple places where each instance needs a distinct identifier, you defeat the purpose. Generate a fresh one for each record or use case.
Using a UUID where a sequential ID would be clearer. UUIDs are excellent for distributed systems where sequential IDs would create conflicts. But for simple, single-database applications, sequential integer IDs (1, 2, 3...) are easier to read, debug, and work with. Use UUIDs when you actually need distributed uniqueness.
Storing UUIDs without indexing them. UUIDs used as primary keys in databases need to be indexed. Without an index, queries that look up records by UUID become extremely slow as the dataset grows.
A Universally Unique Identifier (UUID) is a 128-bit label used to identify information in computer systems. The standard format is 8-4-4-4-12 hexadecimal characters separated by hyphens. UUID v4 is randomly generated, giving it effectively zero chance of collision even across different systems.
UUID v1 is generated from the current timestamp and the MAC address of the generating machine — it encodes time and location information. UUID v4 is completely random. v4 is more commonly used because it doesn't expose system information and is simpler to generate.
In theory it's possible, but so unlikely it's effectively impossible. UUID v4 has 2^122 possible values. The probability of generating the same UUID twice is so small it's not a practical concern for any real-world application.
Use UUIDs when you're building distributed systems where multiple databases or services generate IDs independently, when you need IDs that can be generated client-side before hitting the server, or when you don't want to expose sequential information through your IDs.
UUIDs (Universally Unique Identifiers) give any entity — a user, order, session or file — a permanent, collision-free identity that works across systems, databases and time. They're the standard way to uniquely identify data without exposing sequential information or relying on a central authority.