How to Build a Habit Tracker App with SwiftUI (2026)

The 7 Steps to Ship

Each step takes 4–8 hours with the Swift Kit. From scratch, double-to-triple that.

1. 1

   Step 1 — Project setup

   Clone Swift Kit, run setup.sh, pick "Productivity" preset.

   git clone <swift-kit-repo> MyHabitApp
   cd MyHabitApp
   ./setup.sh

2. 2

   Step 2 — Model habits + completions in SwiftData

   Habit owns a list of HabitCompletion records. Completion has a date (normalized to midnight). Use a @Model for native SwiftUI integration.

   import SwiftData
   
   @Model
   final class Habit {
     var name: String
     var emoji: String
     var colorHex: String
     var reminderTime: Date?
     @Relationship(deleteRule: .cascade) var completions: [HabitCompletion] = []
     var createdAt: Date
   
     init(name: String, emoji: String, colorHex: String) {
       self.name = name
       self.emoji = emoji
       self.colorHex = colorHex
       self.createdAt = .now
     }
   }
   
   @Model
   final class HabitCompletion {
     var date: Date  // midnight in user timezone
     var habit: Habit?
   }

3. 3

   Step 3 — Compute streaks (don't store them)

   Walk backward from today, counting consecutive completed days. Computing on read is cheap and avoids stale-data bugs.

   extension Habit {
     var currentStreak: Int {
       let dates = Set(completions.map { Calendar.current.startOfDay(for: $0.date) })
       var streak = 0
       var day = Calendar.current.startOfDay(for: .now)
       while dates.contains(day) {
         streak += 1
         day = Calendar.current.date(byAdding: .day, value: -1, to: day)!
       }
       return streak
     }
   }

4. 4

   Step 4 — Build the habit list + completion toggle

   List of habits with a tap-to-complete circle. Toggling adds or removes today's HabitCompletion. Haptic + animation on complete.

   List {
     ForEach(habits) { habit in
       HStack {
         Text(habit.emoji).font(.title)
         VStack(alignment: .leading) {
           Text(habit.name).font(.headline)
           Text("\(habit.currentStreak) day streak").font(.caption).foregroundStyle(.secondary)
         }
         Spacer()
         Button { toggle(habit) } label: {
           Image(systemName: isCompletedToday(habit) ? "checkmark.circle.fill" : "circle")
             .font(.title)
         }
       }
     }
   }

5. 5

   Step 5 — Calendar heatmap view

   GitHub-style calendar heat map showing last 90 days. Use LazyVGrid with 7 columns. Color intensity scales with completion.

   LazyVGrid(columns: Array(repeating: .init(.fixed(20)), count: 7), spacing: 4) {
     ForEach(last90Days, id: \.self) { day in
       RoundedRectangle(cornerRadius: 4)
         .fill(color(for: day, habit: habit))
         .frame(height: 20)
     }
   }

6. 6

   Step 6 — Schedule push notification reminders

   For each habit with a reminder time, schedule a daily UNCalendarNotificationTrigger. Cap at 64 (Apple's limit on pending notifications). Cancel today's when user marks complete.

   func scheduleReminder(for habit: Habit) async throws {
     guard let time = habit.reminderTime else { return }
     let center = UNUserNotificationCenter.current()
   
     let content = UNMutableNotificationContent()
     content.title = habit.emoji + " " + habit.name
     content.body = "Time to log your habit"
     content.sound = .default
   
     let trigger = UNCalendarNotificationTrigger(
       dateMatching: Calendar.current.dateComponents([.hour, .minute], from: time),
       repeats: true
     )
     let request = UNNotificationRequest(identifier: habit.id.uuidString, content: content, trigger: trigger)
     try await center.add(request)
   }

7. 7

   Step 7 — Paywall gating + ship

   Free tier: 3 habits, basic theme. Premium: unlimited habits, all themes, widget customization, CSV export. RevenueCat handles the rest. Ship with included App Store assets.

   if !subscription.isPremium && habits.count >= 3 { showPaywall = true; return }

Frequently Asked Questions