Mobile Developer

Learn Swift: Apple's modern language for iOS, macOS, server-side, and cross-platform. Strong static types, optionals, value types, expressive closures. Every lesson is hands-on with real swift execution.

Level up from Swift Fundamentals. Optionals in depth, error handling with throws/try, generics, closures and trailing-closure syntax, protocols and protocol extensions. The features that make Swift Swift.

Beyond Swift Intermediate. Property wrappers, key paths, result builders (the SwiftUI engine), unsafe pointers, opaque return types. The features behind Apple's modern frameworks.

Learn Kotlin, JetBrains' JVM language behind modern Android and a clean alternative to Java on the backend. Covers val and var, numeric types and conversions, string templates, null safety, if and when, loops and ranges, functions, lambdas and higher-order functions, lists, maps, sets, sequences, classes and constructors, data and sealed classes, and inheritance with interfaces. Every lesson ends in a hands-on exercise compiled and run by a real Kotlin compiler.

Level up from Kotlin Fundamentals. Data classes, sealed classes, extension functions, scope functions, null safety, collections, smart casts. The features that make Kotlin feel modern after Java.

Beyond Kotlin Intermediate. Coroutines for async, channels and flow, DSL builders with @DslMarker, type-safe builders, inline + reified generics. The features that scale Kotlin from Android apps to backend services.

Learn Objective-C: the language Apple was built on. iOS apps used it from 2007 until Swift took over in 2014, but billions of lines of Foundation, UIKit, and AppKit are still Objective-C — and Swift interops directly with it. Smalltalk-style messaging on top of C.

Level up from Objective-C Fundamentals. Categories, protocols, blocks, NSArray/NSDictionary, NSError, ARC. The features that make ObjC powerful — and quietly weird.

Learn SQL: the language for talking to databases. Used by literally every backend that stores anything. SELECT, JOIN, GROUP BY, aggregates, subqueries — once you have these you can answer any question your data can answer.

Level up from SQL Fundamentals. Subqueries, CTEs, window functions, set operations, transactions, indexes. The SQL features serious analytics and reporting use every day.

Implement JWT (JSON Web Tokens) end-to-end: base64url encoding, signing with HS256/RS256, claim validation, key rotation via kid, and defenses against the well-known JWT attacks (alg=none, key confusion, weak secrets). Used by every modern auth system.