kotlinx-uuid-core

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

This core module contains the serializable UUID class.

Creating from a UUID string

val uuid = UUID("1b3e4567-e99b-13d3-a476-446657420000")
val guid = UUID("{1b3e4567-e99b-13d3-a476-446657420000}")

Generating UUID4 using random

// using a default SecureRandom implementation
val uuid = UUID()

// use custom Kotlin Random instance
val uuid = UUID.generateUUID(yourRandom)

Generating UUID5 using hash

kotlinx-uuid provides the ability to generate uuids by hashing names (Only SHA-1 is supported at the moment).

val appNamespace = UUID("my-app-uuid")
val agentId = UUID.generateUUID(appNamespace, "agentId")

The other alternative is to generate UUID by hashing bytes (similar to java.util.UUID.nameUUIDFromBytes).

val uuid = UUID.generateUUID(bytes)

Note that unlike java.util.UUID, kotlinx's generateUUID doesn't support MD5, so the blind migration from Java to kotlin-uud may lead to changing UUIDs.

UUID7 Draft

This library contains experimental support for UUIDv7 according to this draft IETF.

val unixTimestamp = 42 // 48 bit
val uuid = UUIDv7(unixTimestamp)
uuid.unixTimeStamp // 42

Serializing (kotlinx.serialization)

There are two serializers for UUID: the default one and the binary.

The default serializer does always serialize UUIDs as string primitives.

Json.encodeToString(uuid) == "\"1b3e4567-e99b-13d3-a476-446657420000\""

The additional serializer is useful for binary formats. Because they are not human-readable, and it's possible to reduce size.

val bytes = Protobuf.encodeToByteArray(BinarySerializer, uuid)

Packages

kotlinx.uuid

android

apple

common

jvm

linuxDerivat

mingwX64

kotlinx.uuid.internal

android

apple

common

jvm

linuxDerivat

mingwX64