Generate deterministic RFC 4122 v5 UUIDs by SHA-1 hashing a name within a namespace (DNS, URL, OID, X.500 or custom).. UUID v5 Generator is a free online tool from the ToolsRift Developer Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Choose a namespace (DNS, URL, OID, X.500 or a custom UUID) and enter a name. The tool SHA-1 hashes them to produce a stable version 5 UUID that never changes for that input.
v4 UUIDs are random; v5 UUIDs are deterministic — the same namespace and name always yield the same UUID, ideal for reproducible IDs.
A base UUID identifying the context (like DNS or URL). Combining it with a name prevents collisions between different kinds of inputs.
When you need a stable identifier derived from existing data, such as generating a consistent ID for a URL or username.