What is a UUID decoder?
A UUID decoder explains the structure inside a Universally Unique Identifier. It normalizes common pasted formats, checks that the value is a 128-bit UUID, and shows the version, variant, raw hexadecimal bytes, and copy-ready numeric representations.
UUIDs are often treated as opaque strings, but the version nibble tells you how the identifier was made. Version 4 UUIDs are random, versions 3 and 5 are name-based hashes, and time-ordered versions such as 1, 6, and 7 can carry timestamp information.
When to use it
Use this tool when you need to inspect an identifier from logs, databases, APIs, traces, or test fixtures. It is useful for confirming whether a UUID is random or time-based, converting it to decimal or Base64 for another system, and spotting whether a UUID v1 or v6 node field may expose a MAC-style identifier.
The decoder runs in your browser and does not send UUID values to a server. It accepts canonical UUIDs, urn:uuid: values, braced UUIDs, uppercase input, and 32-character hexadecimal UUIDs without hyphens.
What to watch for
UUID version and variant fields describe the bit layout, not whether the identifier is globally unique in practice. A valid-looking UUID can still be duplicated if it was generated poorly or copied by mistake.
For version 1 and version 6 UUIDs, the node field can look like a MAC address. Modern generators may set the multicast bit and use a random node instead, so treat it as a node identifier unless you control the generator.