UUIDs in 10 Languages — Part 4: Swift, Kotlin, and Elixir

Welcome to Part 4 of the "UUIDs in 10 Languages" series! This time, we're diving into Swift, Kotlin, and Elixir — three modern languages with very different styles and use cases.

Each offers unique ways to work with UUIDs, whether you're building mobile apps or functional distributed systems.

🍎 Swift: UUIDs in iOS/macOS Development

Swift makes UUID handling simple and native, using UUID from the Foundation framework.

🔧 Generate a UUID

swift

import Foundation

let uuid = UUID()
print("UUID: (uuid.uuidString)")

You can also create a UUID from a string:

swift

if let parsed = UUID(uuidString: "550e8400-e29b-41d4-a716-446655440000") {
    print("Valid UUID: (parsed)")
}

📦 Use in Structs and Models

swift

struct User: Identifiable {
    let id: UUID
    let name: String
}

🧠 Best Practices

Use UUID() for in-memory and persistent identifiers
Use UUID().uuidString for storage or URL-safe formats
Don't truncate UUIDs — store the full string or convert to Base64 if needed

🤖 Kotlin: UUIDs for Android and Multiplatform

Kotlin supports UUIDs through JVM libraries, and newer support is emerging for Kotlin Multiplatform.

🔧 Generate a UUID (JVM/Android)

kotlin

import java.util.UUID

fun main() {
    val id = UUID.randomUUID()
    println("UUID: $id")
}

🔁 Parse and Compare

kotlin

val input = "550e8400-e29b-41d4-a716-446655440000"
val parsed = UUID.fromString(input)

if (parsed.version() == 4) {
    println("UUIDv4 detected")
}

✅ In Spring or Ktor apps

Use UUIDs as entity IDs (@Id val id: UUID)
Kotlin + JPA supports UUID as a native type

📦 Kotlin Multiplatform

For kotlinx.uuid support, install the UUID library:

kotlin

implementation("org.jetbrains.kotlinx:kotlinx-uuid-core:0.0.6")

And generate UUIDs:

kotlin

import kotlinx.uuid.UUID
import kotlinx.uuid.generateUUID

val id = generateUUID()
println(id)

🧪 Elixir: Functional UUIDs the Ecto Way

Elixir offers robust UUID support through Ecto.UUID and database type integrations.

🔧 Generate a UUID

elixir

uuid = Ecto.UUID.generate()
IO.puts("UUID: #{uuid}")

🧱 Ecto Schema Example

elixir

defmodule MyApp.User do
  use Ecto.Schema
  import Ecto.Changeset

  @primary_key {:id, :binary_id, autogenerate: true}
  schema "users" do
    field :name, :string
    timestamps()
  end

  def changeset(user, attrs) do
    user
    |> cast(attrs, [:name])
    |> validate_required([:name])
  end
end

> :binary_id maps to a UUID type in most databases (e.g., uuid in Postgres)

💡 Cast and Validate UUIDs

elixir

case Ecto.UUID.cast("invalid-uuid") do
  {:ok, uuid} -> IO.inspect(uuid)
  :error -> IO.puts("Invalid UUID")
end

🧘 Summary of UUID APIs

Language	Generate	Parse/Validate	DB-Friendly	Notes
Swift	`UUID()`	`UUID(uuidString:)`	✅ via CoreData	Native, clean UUID string output
Kotlin	`UUID.randomUUID()`	`UUID.fromString()`	✅ (JPA, Spring)	JVM-friendly + Multiplatform lib
Elixir	`Ecto.UUID.generate()`	`Ecto.UUID.cast/1`	✅ (binary_id)	Works great with Phoenix & Ecto

Final Thoughts

Swift, Kotlin, and Elixir all provide solid, idiomatic UUID support — whether you're working in OOP, mobile, or functional paradigms.

Swift makes UUIDs simple and elegant
Kotlin lets you work across JVM and multiplatform environments
Elixir integrates UUIDs deeply into its database tooling

Use UUIDs wisely, validate inputs, and never — ever — truncate your identifiers in a fit of front-end formatting fancy.

📦 That wraps Part 4. See you next time for more UUID magic!

"UUIDs in 10 Languages" Part 4: Swift, Kotlin, and Elixir