UUID v5 Generator
Developer
Version-5 UUIDs are generated by hashing a namespace UUID together with a name using SHA-1, so they're deterministic: the same namespace and name always give the same UUID, unlike the random version 4. That makes them ideal for stable, reproducible identifiers derived from things like URLs, domain names or paths — no database lookup needed to get the same ID again. Pick one of the standard namespaces (DNS, URL, OID, X.500) or paste your own namespace UUID, then enter a name. Everything is hashed locally in your browser with the Web Crypto API.
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How to use
- Choose a namespace — DNS, URL, OID, X.500, or a custom UUID you paste in.
- Enter the name to hash (for example a domain or URL).
- Copy the resulting version-5 UUID; it's stable for the same namespace and name.
Frequently asked questions
- How is v5 different from v4?
- Version 4 is random — every call gives a different UUID. Version 5 is deterministic: it's the SHA-1 hash of the namespace plus the name, so identical inputs always produce an identical UUID.
- What are the standard namespaces?
- RFC 4122 defines four: DNS, URL, OID and X.500, each a fixed UUID. Use DNS for domain names, URL for URLs, or supply your own namespace UUID for your application.
- Is v5 secure or reversible?
- It's a one-way hash, so you can't recover the name from the UUID, but it isn't a secret — anyone with the same namespace and name gets the same value. Don't use it to hide data.
- Why not version 3?
- Version 3 uses MD5 instead of SHA-1. The Web Crypto API in browsers doesn't support MD5, and v5 is the recommended modern equivalent, so this tool produces v5.
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