This architecture design ensures that the real-time quiz feature functions smoothly with accurate and consistent score updates and prompt leaderboard changes

• Here is the C4 diagram

• Here is the Seuquence diagram

• Client Applications: Interfaces for users to participate in the quiz, answer questions, and view the leaderboard.
• Kong API Gateway: Acts as a centralized entry point for handling API requests and routing them appropriately.
• Redis Cache Layer: Stores temporary data such as user scores, quiz sessions, and leaderboard information for quick access.
• Transaction Server: Manages quiz logic, real-time scoring, and leaderboard updates.
• Kafka Message Bus: Facilitates real-time messaging and communication between components for score updates and leaderboard changes.
• WebSocket: Enables bidirectional and real-time communication between clients and the server for instant updates.

• Clients request to join a quiz session through the Kong API Gateway and are assigned a unique quiz ID by the Transaction Server.
• Multiple users can join the same quiz session simultaneously, managed by the Transaction Server.
• Users join a quiz session using a unique quiz ID.
• The API Gateway forwards the request to the Transaction Server, which then checks and adds the user to the quiz session in the Redis Cache.
• Confirmation of the user joining is sent back through the same path to the Client App, which confirms it to the User.

• When users submit answers, the Transaction Server processes them, updates scores in Redis, and sends real-time score updates via Kafka.
• Clients receive score updates in real-time through WebSocket connections.
• When a user submits an answer, it is sent from the Client App via WebSocket to the Transaction Server.
• The Transaction Server processes the answer and updates the user score in the Redis Cache.
• A confirmation of the score update is sent back through the same path.
• The Transaction Server publishes the score update message to the Kafka Message Bus.
• The Kafka Message Bus broadcasts the score update to all relevant client applications, which then display the updated score.

• The Transaction Server updates the leaderboard in Redis as scores change and broadcasts these updates via Kafka.
• Clients receive prompt leaderboard updates through WebSockets to display the current standings.