TOML

UUID/GUID (Universally/Globally Unique Identifier) - TOML

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are 128-bit unique identifiers used in software systems. Standardized by RFC 4122 and RFC 9562, they can be generated independently without a central coordinating authority and have an extremely low probability of duplication. They are widely used for database primary keys, distributed system identifiers, API keys, and more.

UUID GUID identifier RFC 4122 RFC 9562 database distributed systems

[[items]]
code = "v1"
slug = "uuid-v1"
name = "UUIDv1 (Gregorian Time-Based)"
description = "Time-based UUID using timestamp and MAC address."
algorithm = "Time-based + MAC address"
recommended = false
sortable = true

[[items]]
code = "v2"
slug = "uuid-v2"
name = "UUIDv2 (DCE Security)"
description = "DCE Security UUID with embedded POSIX UID/GID."
algorithm = "DCE Security with POSIX ID"
recommended = false
sortable = true

[[items]]
code = "v3"
slug = "uuid-v3"
name = "UUIDv3 (Name-Based, MD5)"
description = "Name-based UUID generated using MD5 hash of namespace and name."
algorithm = "MD5 hash of namespace + name"
recommended = false
sortable = false

[[items]]
code = "v4"
slug = "uuid-v4"
name = "UUIDv4 (Random)"
description = "The most commonly used random-generated UUID."
algorithm = "Random 122 bits"
recommended = true
sortable = false

[[items]]
code = "v5"
slug = "uuid-v5"
name = "UUIDv5 (Name-Based, SHA-1)"
description = "Name-based UUID generated using SHA-1 hash of namespace and name."
algorithm = "SHA-1 hash of namespace + name"
recommended = true
sortable = false

[[items]]
code = "v6"
slug = "uuid-v6"
name = "UUIDv6 (Reordered Time-Based)"
description = "Field-compatible reordering of UUIDv1 with improved database locality."
algorithm = "Reordered UUIDv1 timestamp"
recommended = false
sortable = true

[[items]]
code = "v7"
slug = "uuid-v7"
name = "UUIDv7 (Unix Epoch Time-Based)"
description = "The recommended modern time-based UUID using Unix timestamp."
algorithm = "48-bit Unix timestamp + 74-bit random"
recommended = true
sortable = true

[[items]]
code = "v8"
slug = "uuid-v8"
name = "UUIDv8 (Custom)"
description = "Implementation-defined custom UUID format for experimental use."
algorithm = "Implementation-defined custom"
recommended = false
sortable = ""