UUID Generator
Free online UUID generator supporting v1, v4, v5 and v7 / GUID. Create single or multiple unique identifiers instantly for software, databases, APIs and distributed systems. RFC 9562 compliant.
Click Generate to create a UUID
About this tool
Generate universally unique identifiers (UUID/GUID) with one click. This tool supports UUID v4 (random), v7 (time-ordered, ideal for database keys), v1 (timestamp-based) and v5 (namespace + name, deterministic). UUID — also known as GUID (Globally Unique Identifier) — is a 128-bit identifier standardized by RFC 9562 (formerly RFC 4122). Generate a single value or a bulk list for testing, database seeding and distributed systems.
Features
How the UUID Generator Works
Pick a UUID version, then click generate to create an identifier instantly in your browser. v4 and v7 are produced from cryptographically secure random bytes; v1 embeds a timestamp; v5 derives a deterministic value from a namespace and a name via SHA-1. Enable multiple generation to create a batch. Every UUID follows the format defined by RFC 9562, making the tool useful for testing, development, integrations and data modeling.
Main Use Cases
- Software DevelopmentCreate unique identifiers for entities, records, and internal references within your application architecture.
- Database Primary KeysUse v7 for time-ordered primary keys that avoid index fragmentation, or v4 for opaque external identifiers.
- APIs and MicroservicesAssign unique resource IDs, request IDs, and correlation IDs to track transactions across services.
- Testing and Data SeedingProduce batches of realistic unique values for QA testing, database fixtures, and automated test suites.
- Deterministic IDsUse v5 to derive a stable, reproducible identifier from a namespace and a known name, such as a URL or domain.
How to Use This Tool
Choose a version
Select v4, v7, v1 or v5. For v5, also provide a namespace and a name.
Generate
Click the generate button, or toggle 'Generate Multiple' to create a batch of 2–100. Your UUID(s) appear instantly.
Copy
Click the copy icon next to any UUID, or use 'Copy All' to copy the entire list at once.
Questions & Answers
UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 9562 (which replaced RFC 4122 in 2024). It allows independent systems to generate unique values without any central coordination.
Use v4 for general-purpose random IDs, tokens and public identifiers. Use v7 for database primary keys, since its timestamp prefix keeps inserts sequential and avoids index fragmentation. Use v1 when you need a timestamp embedded the classic way, and v5 when you need a deterministic ID derived from a name.
v4 is fully random, so it reveals no creation time but scatters across database indexes. v7 places a millisecond timestamp in the leading bits, making IDs time-sortable and far more efficient as primary keys in B-tree indexes like PostgreSQL or MySQL.
Yes. v5 is derived from a namespace UUID and a name using SHA-1, so the same inputs always produce the same UUID. This is useful when you need a stable identifier for a known value, such as a URL or username.
UUID and GUID refer to the same standard. GUID (Globally Unique Identifier) is Microsoft's name for UUID. Both follow RFC 9562 and are interchangeable in most contexts.