Requirements

Functional Requirements:

• Allow users to post, edit, and delete advertisements with title, description, category, price, and location.
• Allow users to browse and view listings organized by categories and subcategories (jobs, housing, services, for sale, etc.).
• Enable users to search for listings using keywords, and filter by category, price range, location, and date posted.
• Enable user registration and authentication with email/password or social login to post and manage their listings.
• Allow users to upload photos for their listings; store, resize, and serve images via CDN.

Non-Functional Requirements:

• The system should display high availability for view of the ads anf the availability if global should depend on the GCC's.
• Search caching, so that searches are optimized so as to improve response time
• Howizontal Scalability should be in place where traffic increases so as to handle writes and reads.

Capacity Estimation

Estimate the scale of the system. Consider daily active users, read/write ratio, storage requirements, bandwidth, and any relevant QPS calculations...

API Design

1. GET /listing
2. POST /addListing
3. POST /deleteListing

High-Level Design

1. User Registration to post ads (AZure Auth)
2. API Gateway - to let in authenticated users. Authenticated by role.
3. A user with agent role should be able to edit their posts

Database Design

Define the data model. Identify the main entities, their attributes, and relationships. Consider the choice of database type (SQL vs NoSQL) and justify your decision based on access patterns...

Detailed Component Design

Deep dive into 2-3 key components. Explain how they work, how they scale, discuss tradeoffs, capacity, and any relevant algorithms or data structures.