UUID Generator
A UUID (Universally Unique Identifier) Generator creates RFC 4122-compliant 128-bit identifiers in the format xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. UUID v4 uses cryptographically random bits, making collision probability astronomically low.
What is UUID Generator?
UUIDs are used as primary keys in distributed databases, tracking tokens in event systems, session identifiers, and idempotency keys in APIs. This generator uses crypto.randomUUID() (supported in all modern browsers) to produce v4 UUIDs from the operating system's cryptographic entropy source, ensuring true randomness and negligible collision probability (about 1 in 5.3 × 10^36 pairs).
Use Cases
- Database primary keys in distributed systems.
- Idempotency keys for API requests.
- Unique session or tracking tokens.
- File and asset naming in cloud storage.
How to Use It
Click Generate to produce a UUID.
Use the Bulk option to generate up to 100 UUIDs at once.
Click Copy All to transfer all UUIDs to your clipboard.
Pros
- Uses crypto.randomUUID() for true randomness.
- Bulk generation for testing fixtures.
- RFC 4122 compliant output.
Limitations
- UUID v4 is not sortable—use ULID or UUID v7 if sort order matters.
Best Practices
- Use UUID v4 for most applications—it provides the strongest randomness.
- Use UUID v7 (time-ordered) when you need sortable UUIDs for database performance.
Common Mistakes to Avoid
- Using sequential integers instead of UUIDs in distributed systems causes collision.
- Storing UUIDs as strings instead of native UUID columns in PostgreSQL wastes storage.
FAQs
What is the difference between UUID v1 and v4?
v1 is time-based and includes the machine MAC address (privacy concern). v4 is entirely random and is recommended for most uses.
How unique are UUIDs really?
The probability of generating two identical v4 UUIDs is 1 in 2^122—effectively impossible in any realistic scenario.