🎓 KAAFI – Low-Cost Niche Course Platform

Learnign platform for gaining life skills and enhanace your regular life

Version: 1.0 | Date: October 28, 2025 | Status: 📋 Active

**📷ScreenShots**

📖 Table of Contents

• Introduction
• Project Scope
• System Overview
• Key Features
• Technical Architecture
• Functional Requirements
• Non-Functional Requirements
• User Roles
• Development Stack
• Project Team

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🎯 Introduction

Purpose

KAAFI is an innovative online platform dedicated to selling low-cost, practical micro-courses that teach everyday and vocational skills. This Software Requirements Specification (SRS) document defines the functional and non-functional requirements to guide the development, testing, and deployment of the system.

Vision

To create an accessible learning ecosystem where anyone can acquire practical skills at an affordable price, focusing on simplicity and low-bandwidth optimization.

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🔭 Project Scope

KAAFI enables:

For Instructors

• Create and sell short, affordable niche courses
• Examples: Fixing AC filters, basic plumbing, emergency safety skills
• Manage course content and track earnings

For Students

• Browse, purchase, and learn practical skills
• Access short videos and step-by-step lessons
• Track learning progress

For Administrators

• Manage users, transactions, and content quality
• Oversee platform operations
• Generate system reports

Platform: Web application with future mobile app support
Focus: Lightweight, responsive, low-bandwidth optimized

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🏗️ System Overview

Core Components

Component	Description
👤 User Management	Registration, authentication, profile management
📚 Course System	Creation, publishing, enrollment, and streaming
💳 Payment Gateway	Secure low-cost transaction processing
⭐ Review System	Ratings, reviews, and feedback
🛠️ Admin Dashboard	Platform oversight and management
🔍 Discovery Engine	Search, filtering, and recommendations

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✨ Key Features

🎓 Course Management

• Create/edit courses with videos, descriptions, and resources
• Course approval workflow
• Progress tracking for students
• Resume from last watched position

💰 Affordable Pricing

• All courses priced under 1000 TK
• Multiple payment options (Bkash, Nagad)
• Secure transaction handling

📱 Accessibility

• Optimized for low-bandwidth environments
• Simple UI for low-tech literacy users
• Mobile-responsive design
• WCAG 2.1 compliance

🔒 Security

• Secure authentication (phone-based)
• HTTPS data transmission
• PCI-DSS compliance for payments
• Regular security updates

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🏗️ Technical Architecture

Tech Stack

Frontend:

• Primary: Kotlin/Flutter
• Target: Web, iOS, Android

Backend:

• Language: Kotlin/Java/python
• Framework: Spring Boot / Ktor/FastApi/Flask
• API: RESTful APIs
• For now using supabase

Database:

• Primary: Supabase Database

Storage:

• Videos: AWS S3 / Cloud Storage/supabase storage
• Files: Cloud-based storage

Infrastructure:

• Cloud: AWS / Firebase / Azure/Supabase
• CI/CD: GitHub Actions / Jenkins

System Diagram

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📋 Functional Requirements

👥 User Management (FR1-FR3)

• FR1: Phone-based registration
• FR2: Secure login/logout
• FR3: Profile management (photo, bio, etc.)

📚 Course Management (FR4-FR7)

• FR4: Instructor course CRUD operations
• FR5: Course structure (title, description, price, videos, files)
• FR6: Student enrollment and access
• FR7: Admin course approval/rejection

💳 Payment System (FR8-FR10)

• FR8: Secure payments (Bkash/Nagad integration)
• FR9: Transaction recording
• FR10: Refund processing

🎬 Course Viewing (FR11-FR13)

• FR11: Low-bandwidth video streaming
• FR12: Resume from last position
• FR13: Progress tracking

⭐ Ratings & Reviews (FR14-FR15)

• FR14: Rating and commenting system
• FR15: Average rating display

🔍 Search & Discovery (FR16-FR17)

• FR16: Search by keyword, instructor, category
• FR17: Filter by price, popularity, rating

🔔 Notifications (FR18)

• FR18: Email/push notifications for purchases and updates

🛠️ Admin Panel (FR19-FR20)

• FR19: Sales, user, and course reports
• FR20: User account management

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⚡ Non-Functional Requirements

🚀 Performance

• NFR1: Page load time < 2 seconds average
• NFR2: Support 1000+ concurrent users

🔒 Security

• NFR3: Secure password hashing (bcrypt/Argon2)
• NFR4: HTTPS for all data transmission
• NFR5: Regular security audits

🎨 Usability

• NFR6: Intuitive UI for first-time users
• NFR7: WCAG 2.1 accessibility compliance
• NFR8: Mobile-responsive design

🛡️ Reliability

• NFR9: 99.5% system uptime
• NFR10: Daily automated database backups
• NFR11: Error monitoring and logging

🧩 Maintainability

• NFR12: Modular, well-documented code
• NFR13: API versioning support
• NFR14: Comprehensive testing suite

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👥 User Roles

Role	Description	Access Level	Key Permissions
👨‍🎓 Student	Learns practical skills	🔓 Low	Browse, purchase, watch courses, rate & review
👨‍🏫 Instructor	Creates and sells courses	🔑 Medium	Create/manage courses, view earnings, track students
👑 Admin	Manages platform operations	🔐 High	User management, course approval, system reports, settings

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📊 Operating Environment

Supported Platforms

🌐 Web Browsers:

• Chrome (latest)
• Safari (latest)
• Edge (latest)
• Firefox (latest)

📱 Mobile:

• Android 8.0+
• iOS 13+

Infrastructure Requirements

☁️ Cloud Services:

• AWS / Google Cloud / Azure /Supabase
• Firebase/Supabase for authentication (optional)
• CDN for video delivery

🗄️ Database:

• PostGreSql
• Regular backup system

📦 Storage:

• Video: Cloud storage with CDN
• Static: Object storage

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⚠️ Constraints & Dependencies

Constraints

• Courses must be priced under 1000 TK
• Must comply with PCI-DSS for payments
• UI must be simple for low-tech literacy users
• Must function in low-bandwidth environments

Dependencies

• Third-party payment APIs (Bkash, Nagad)
• Internet connectivity for users
• Cloud service providers
• Video encoding services

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🚀 Getting Started

Prerequisites

• Dart 3.5
• Flutter for frontend
• Supabase Account
• Git

Backend setup

Frontend setup

flutter pub get flutter run

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🤝 SQL query of Supabase Postgre

📊 KAAFI Database Schema

PostgreSQL Database Design for Low-Cost Course Platform

🗂️ Database Overview

sql -- Database: kaafi_platform -- Schema: public -- Total Tables: 16 -- Relationships: 12 Foreign Keys -- Features: UUID Primary Keys, JSON Arrays, Real-time Capable

📈 Entity Relationship Diagram

🏗️ Table Structures

👥 Core User Tables

1. User Table - Main user authentication and profile

sql CREATE TABLE public."User" ( "userId" TEXT NOT NULL PRIMARY KEY, name TEXT, email TEXT, role TEXT, img TEXT NOT NULL DEFAULT ''''''::TEXT, enrolled_courses TEXT[] NOT NULL DEFAULT '{}'::TEXT[], wish_list TEXT[] NOT NULL DEFAULT '{}'::TEXT[], cart TEXT[] NOT NULL DEFAULT '{}'::TEXT[], created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

2. Student Table - Student-specific data

sql CREATE TABLE public."Student" ( "studentId" UUID NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY, "enrolledCourses" JSON[], progress JSON[], "userId" BIGINT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

3. Instructors Table - Instructor profiles

sql CREATE TABLE public."Instructors" ( "instructorId" TEXT NOT NULL PRIMARY KEY, "userId" TEXT, bio TEXT, qualifications TEXT, rating DOUBLE PRECISION, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

📚 Course Management Tables

4. Courses Table - Course catalog

sql CREATE TABLE public."Courses" ( "courseId" UUID NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY, "instructorId" UUID DEFAULT gen_random_uuid(), "categoryId" UUID DEFAULT gen_random_uuid(), title TEXT DEFAULT ''::TEXT, description TEXT DEFAULT ''::TEXT, price DOUBLE PRECISION DEFAULT 0, status JSONB, url TEXT NOT NULL DEFAULT ''::TEXT, thumbnail TEXT NOT NULL DEFAULT ''::TEXT, "instructorName" TEXT, enrolled BIGINT, rating DOUBLE PRECISION, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

5. Category Table - Course categorization

sql CREATE TABLE public."Category" ( "categoryId" TEXT NOT NULL PRIMARY KEY, name TEXT, "parentCategoryId" TEXT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

6. Sections Table - Course sections/modules

sql CREATE TABLE public."Sections" ( "sectionId" TEXT NOT NULL PRIMARY KEY, "courseId" TEXT, title TEXT, "order" BIGINT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

7. Lesson Table - Individual lessons

sql CREATE TABLE public."Lesson" ( "lessonId" TEXT NOT NULL PRIMARY KEY, "sectionId" TEXT, title TEXT DEFAULT ''::TEXT, content TEXT DEFAULT ''::TEXT, "videoUrl" TEXT DEFAULT ''::TEXT, duration BIGINT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW() );

🎓 Learning & Assessment Tables

8. Enrollements Table - Course enrollment tracking

sql CREATE TABLE public."Enrollements" ( "enrollmentId" TEXT NOT NULL PRIMARY KEY, "studentId" UUID, "courseId" UUID NOT NULL DEFAULT gen_random_uuid(), "enrollmentDate" TIMESTAMP WITH TIME ZONE, progress DOUBLE PRECISION, status TEXT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), FOREIGN KEY ("courseId") REFERENCES "Courses"("courseId") ON DELETE SET NULL, FOREIGN KEY ("studentId") REFERENCES "Student"("studentId") );

9. Quizzes Table - Course assessments

sql CREATE TABLE public."Quizzes" ( "quizId" TEXT NOT NULL PRIMARY KEY, "courseId" UUID, title TEXT, "passingGrade" BIGINT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), FOREIGN KEY ("courseId") REFERENCES "Courses"("courseId") );

10. Questions Table - Quiz questions

sql CREATE TABLE public."Questions" ( "questionId" TEXT NOT NULL PRIMARY KEY, "quizId" TEXT, text TEXT, options JSONB NOT NULL, "correctAnswer" TEXT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), FOREIGN KEY ("quizId") REFERENCES "Quizzes"("quizId") );

11. Certificates Table - Achievement certificates

sql CREATE TABLE public."Certificates" ( "certId" TEXT NOT NULL PRIMARY KEY, "studentId" UUID, "courseId" UUID, "issueDate" TIMESTAMP WITH TIME ZONE, criteria TEXT, FOREIGN KEY ("courseId") REFERENCES "Courses"("courseId"), FOREIGN KEY ("studentId") REFERENCES "Student"("studentId") );

💬 Community & Engagement Tables

12. Review Table - Course reviews and ratings

sql CREATE TABLE public."Review" ( "reviewId" TEXT NOT NULL PRIMARY KEY, "courseId" TEXT, "studentId" UUID, rating BIGINT, comment TEXT, date TIMESTAMP WITH TIME ZONE, FOREIGN KEY ("studentId") REFERENCES "Student"("studentId") );

13. Forum Table - Discussion forums

sql CREATE TABLE public."Forum" ( "forumId" TEXT NOT NULL PRIMARY KEY, "courseId" UUID, topic TEXT, "moderatorId" TEXT, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), FOREIGN KEY ("courseId") REFERENCES "Courses"("courseId"), FOREIGN KEY ("moderatorId") REFERENCES "User"("userId") );

14. Posts Table - Forum posts

sql CREATE TABLE public."Posts" ( "postId" TEXT NOT NULL PRIMARY KEY, "forumId" TEXT, "authorId" TEXT, content TEXT, date TIMESTAMP WITH TIME ZONE, "courseId" UUID, FOREIGN KEY ("authorId") REFERENCES "User"("userId"), FOREIGN KEY ("courseId") REFERENCES "Courses"("courseId"), FOREIGN KEY ("forumId") REFERENCES "Forum"("forumId") );

💰 Transaction & Notification Tables

15. Payments Table - Payment transactions

sql CREATE TABLE public."Payments" ( "paymentId" UUID NOT NULL PRIMARY KEY, "enrollmentId" TEXT, amount DOUBLE PRECISION, date TIMESTAMP WITH TIME ZONE, status TEXT, method TEXT, FOREIGN KEY ("enrollmentId") REFERENCES "Enrollements"("enrollmentId") );

16. Notifications Table - User notifications

sql CREATE TABLE public."Notifications" ( "notifId" TEXT NOT NULL PRIMARY KEY, "userId" TEXT, message TEXT, "isRead" BOOLEAN, created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(), FOREIGN KEY ("userId") REFERENCES "User"("userId") );

🔐 Row Level Security (RLS) Policies

sql -- Example RLS policies for Supabase ALTER TABLE "User" ENABLE ROW LEVEL SECURITY; ALTER TABLE "Courses" ENABLE ROW LEVEL SECURITY; ALTER TABLE "Enrollements" ENABLE ROW LEVEL SECURITY;

-- User can only see their own data CREATE POLICY "Users can view own profile" ON "User" FOR SELECT USING (auth.uid()::text = "userId");

-- Public can view published courses CREATE POLICY "Anyone can view published courses" ON "Courses" FOR SELECT USING (status->>'published' = 'true');

-- Students can only see their own enrollments CREATE POLICY "Students see own enrollments" ON "Enrollements" FOR SELECT USING ("studentId" IN ( SELECT "studentId" FROM "Student" WHERE "userId" = auth.uid()::text ));

📊 Database Statistics

Metric	Value	Description
Total Tables	16	Core database entities
Primary Keys	16	All tables have primary keys
Foreign Keys	12	Relationship constraints
UUID Columns	8	Secure identifier columns
JSON/JSONB Columns	6	Flexible data storage
Array Columns	4	Efficient list storage
Timestamp Columns	14+	Audit trail support

🎨 Index Recommendations

sql -- Performance optimization indexes CREATE INDEX idx_courses_instructor ON "Courses"("instructorId"); CREATE INDEX idx_courses_category ON "Courses"("categoryId"); CREATE INDEX idx_enrollments_student ON "Enrollements"("studentId"); CREATE INDEX idx_enrollments_course ON "Enrollements"("courseId"); CREATE INDEX idx_review_course ON "Review"("courseId"); CREATE INDEX idx_lesson_section ON "Lesson"("sectionId"); CREATE INDEX idx_posts_forum ON "Posts"("forumId"); CREATE INDEX idx_notifications_user ON "Notifications"("userId");

🔄 Triggers for Data Integrity

sql -- Auto-update timestamps CREATE OR REPLACE FUNCTION update_updated_at_column() RETURNS TRIGGER AS $$ BEGIN NEW.updated_at = NOW(); RETURN NEW; END; $$ language 'plpgsql';

-- Apply to relevant tables CREATE TRIGGER update_user_updated_at BEFORE UPDATE ON "User" FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_courses_updated_at BEFORE UPDATE ON "Courses" FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

📈 Sample Queries

1. Get Course with Details

sql SELECT c."courseId", c.title, c.description, c.price, c.rating, i.name as instructor_name, cat.name as category_name, COUNT(e."enrollmentId") as total_enrollments FROM "Courses" c LEFT JOIN "Instructors" i ON c."instructorId" = i."instructorId" LEFT JOIN "Category" cat ON c."categoryId" = cat."categoryId" LEFT JOIN "Enrollements" e ON c."courseId" = e."courseId" GROUP BY c."courseId", i.name, cat.name;

2. Student Progress Report

sql SELECT s."studentId", u.name as student_name, COUNT(DISTINCT e."courseId") as courses_enrolled, AVG(e.progress) as avg_progress, COUNT(DISTINCT cert."certId") as certificates_earned FROM "Student" s JOIN "User" u ON s."userId"::text = u."userId" LEFT JOIN "Enrollements" e ON s."studentId" = e."studentId" LEFT JOIN "Certificates" cert ON s."studentId" = cert."studentId" GROUP BY s."studentId", u.name;

3. Instructor Performance

sql SELECT i."instructorId", u.name as instructor_name, i.rating, COUNT(DISTINCT c."courseId") as total_courses, SUM(c.enrolled) as total_enrollments, AVG(r.rating) as avg_course_rating FROM "Instructors" i JOIN "User" u ON i."userId" = u."userId" LEFT JOIN "Courses" c ON i."instructorId"::text = c."instructorId"::text LEFT JOIN "Review" r ON c."courseId"::text = r."courseId" GROUP BY i."instructorId", u.name, i.rating;

🚀 Migration Commands

bash

Apply schema to Supabase

supabase db reset

Or apply specific migrations

supabase migration up

Generate TypeScript types

supabase gen types typescript --schema public > types/database.ts

Set up real-time subscriptions

supabase realtime start

🛠️ Database Health Check

sql -- Check table sizes SELECT schemaname, tablename, pg_size_pretty(pg_total_relation_size(schemaname||'.'||tablename)) as total_size FROM pg_tables WHERE schemaname = 'public' ORDER BY pg_total_relation_size(schemaname||'.'||tablename) DESC;

-- Check foreign key constraints SELECT tc.table_schema, tc.table_name, kcu.column_name, ccu.table_schema AS foreign_table_schema, ccu.table_name AS foreign_table_name, ccu.column_name AS foreign_column_name FROM information_schema.table_constraints AS tc JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name AND tc.table_schema = kcu.table_schema JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name AND ccu.table_schema = tc.table_schema WHERE tc.constraint_type = 'FOREIGN KEY' AND tc.table_schema = 'public';

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💡 Database Features Summary

✅ Normalized Schema - Minimal redundancy
✅ UUID Primary Keys - Secure and scalable
✅ JSON Support - Flexible data structures
✅ Audit Trails - Created/Updated timestamps
✅ RLS Ready - Row-level security compatible
✅ Real-time Capable - Supabase subscriptions
✅ Performance Optimized - Index recommendations

"Designed for scalability, security, and real-time updates"

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🤝 Contributing

We welcome contributions! Please see our Contributing Guidelines for details.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit changes (git commit -m 'Add some AmazingFeature')
4. Push to branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

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📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🌟 Star us on GitHub if you find this project useful!

"Empowering practical skills, one micro-course at a time."

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Kaafi