UUID Generator
Generate UUID identifiers - supports v1, v4, v6, and v7 formats
Free online UUID generator to create unlimited universally unique identifiers instantly. Generate UUIDs in bulk with v1, v4, v6, v7 formats. Perfect for database primary keys, API IDs, and distributed systems. v4 is random, v6/v7 are database-friendly. Copy individual or bulk with one click. Cryptographically secure, 100% client-side.
Max 100 UUIDs per generation
What Is a UUID?
A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit number used to uniquely identify records, resources, or entities in software systems. UUIDs are formatted as 32 hexadecimal characters separated by hyphens: 550e8400-e29b-41d4-a716-446655440000. They are widely used in databases, distributed systems, APIs, and microservices where unique identification without a central authority is required.
UUID Versions Explained
UUID v1 — Timestamp-based
Generated from the current timestamp and a node identifier. Provides natural time-ordering but may expose creation time. Used in Cassandra and some legacy systems.
UUID v4 — Random
Generated using 122 bits of cryptographic randomness. The most commonly used version — ideal for general-purpose unique identifiers. Collision probability is astronomically low.
UUID v6 — Reordered Timestamp
Similar to v1 but with the timestamp bits reordered for better database indexing performance. Ideal for use as primary keys in PostgreSQL, MySQL, or MongoDB.
UUID v7 — Unix Timestamp + Random
The newest standard. Combines a millisecond-precision Unix timestamp with random data. Time-ordered, sortable, and database-friendly. Recommended for new projects over v1 and v4.
When to Use UUIDs
- Database primary keys — especially in distributed or sharded databases
- API resource identifiers — safer than auto-incrementing IDs (prevents enumeration attacks)
- Session tokens, correlation IDs, and trace IDs in microservice architectures
- File naming to prevent collisions in storage systems (S3, Azure Blob, GCS)
- Idempotency keys for payment APIs (Stripe, PayPal)