Product Requirements (PRD)
Detailed feature specifications for the Fit Tracker mobile application.
1. Core Philosophy
Fit Tracker is designed as a "daily movement diary." It promotes gentle, consistent progress over extreme fitness goals. The app is entirely self-contained, prioritizing user privacy with no cloud sync, server requirements, or user accounts.
2. Feature Modules
Home Dashboard
- Personalized greeting with user's name and date.
- Circular progress ring for daily steps against a custom goal.
- "Pause tracking" toggle.
- Metrics cards for Calories (kcal), Distance (km), and Active minutes.
- "Water is self-care" hydration tracker (up to 8 glasses) with +/- controls.
Progress Tracking
- Visual bar chart for the "Last 7 days" step history.
- Calculations for Weekly Total, Current Streak, and Best Day.
- Chronological list view of daily step history.
- Shareable weekly progress capability.
Profile & Goals
- "My little corner" customizable profile.
- Inputs for Name, Daily Step Goal, Weight (kg), Height (cm), and Stride Length (m).
- App version info and "Reset all my data" emergency button.
Sparkle Collection
- Gamified achievement badges (Locked/Unlocked states).
- Milestones: First 1k steps, 5K, 10K.
- Streaks: 3-day and 7-day.
- Hydration Hero (Completing 8 glasses in a day).
Technical Specs (TRD)
System architecture and data models.
Architecture: Local-First Offline App
Storage Engine: SQLite / AsyncStorage
Network: 0 external API calls required.
interface UserProfile {
name: string;
stepGoal: number; // Default: 500
weightKg: number;
heightCm: number;
strideLengthM: number; // e.g., 0.73
}
interface DailyLog {
date: string; // YYYY-MM-DD
steps: number;
waterGlasses: number; // Max 8
}
Distance & Calculation Engine
The application estimates physical distance by multiplying the daily steps integer by the user's defined strideLengthM float variable. Calories and active minutes are mathematically derived using baseline formulas based on steps and body weight, requiring no GPS tracking to preserve battery and privacy.
User Manual
How to navigate and use the Fit Tracker app.
1. Setup Your Profile
To get accurate distance and calorie readings, tap the Profile tab at the bottom right. Enter your name, target daily step goal, weight, height, and average stride length. Tap Save my changes.
2. Tracking Your Day
On the Home tab, your steps will automatically log based on your phone's motion sensor. The circular pink bar shows your progress towards your goal.
- Need to stop counting? Tap Pause tracking.
- Drink a glass of water? Tap the + button under the "Water is self-care" section to log up to 8 glasses a day.
3. Viewing Progress & Achievements
Navigate to the Progress tab to see how you've done over the past week. You can see your current streak and your best day.
Tap View my achievements (or check the Profile tab) to view your "Sparkle Collection"—a display of the trophies you have unlocked for hitting step milestones and drinking enough water.