Static vs instance requirements
Differentiate between static (type-level) and instance (object-level) requirements in protocols, and learn how conforming types implement them.
Static vs instance requirements is a free Swift Academy lesson on CoddyKit. This is lesson 3 of 3. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Swift Academy learning path, and your progress syncs across the web and the CoddyKit app. The Swift Academy course includes 3 lessons in total.
Overview
Protocols can demand instance or static members. Knowing which is which helps you design clear APIs.
Instance requirement
Instance requirements must be implemented by each instance of the conforming type.
protocol Drawable {
func draw() -> String
}
struct Circle: Drawable {
func draw() -> String { "Drawing a circle" }
}
print(Circle().draw())Static requirement
Static requirements are satisfied by type-level members (properties or methods).
protocol Identifiable {
static var tag: String { get }
}
struct User: Identifiable {
static var tag: String { "USR" }
}
print(User.tag)Static in classes
Classes may implement static requirements with either static or class (allowing override).
protocol Describable {
static func describeType() -> String
}
class Animal: Describable {
class func describeType() -> String { "Animal type" }
}
print(Animal.describeType())Mixed example
Protocols often mix static and instance requirements for flexibility.
protocol Logger {
static var system: String { get }
func log(_ msg: String)
}
struct ConsoleLogger: Logger {
static let system = "console"
func log(_ msg: String) { print("[\\(Self.system)]", msg) }
}
let logger = ConsoleLogger()
logger.log("hello")Notes
Notes:
- Use static for type-wide info or factories.
- Use instance for per-object behavior.
- Classes can use
classto allow override of static members.
Static vs instance
Quick check: What distinguishes a static requirement?
Recap
Recap: Instance requirements apply to each object. Static requirements apply at the type level. Classes can use class for overridable static members.
Learn Swift with an AI tutor — free
Write and run real code in your browser, get instant help from a 24/7 AI tutor, and pick up where you left off on the web or in the app.
- Courses
- 122
- Lessons
- 409
Frequently Asked Questions
Is the “Static vs instance requirements” lesson free?
Yes — any 3 lessons of the Swift Academy learning path, including “Static vs instance requirements”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Swift Academy course includes 3 lessons in total.
What will I learn in “Static vs instance requirements”?
Differentiate between static (type-level) and instance (object-level) requirements in protocols, and learn how conforming types implement them. You practise Swift Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Swift Academy?
No prior experience is required. Swift Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 3.
How long does the “Static vs instance requirements” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Swift Academy lesson?
Yes. Every Swift Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Protocols & Extensions basics
- Protocol extensions vs type extensions
- Static vs instance requirements