🔧 Best Practices for a .NET 10 Event Ticketing API

How Would You Design a Scalable and Maintainable Event Ticketing API?
Hey everyone,

I’m working on designing a mock event ticketing API, and I want to make sure I’m applying best practices, design patterns, and scalable architecture. I don’t just want a working solution—I want to learn how to write clean, optimized, and maintainable code.

What I’d Love Input On
🔹 Design Patterns – Should I use Factory, Strategy, or something else to handle different booking flows?
🔹Handling Long-Running Operations – Would background tasks, a queue, or a worker service be better than polling?
🔹 Scalability & Maintainability – How would you structure this API to easily add more ticket types in the future?
🔹 Performance Optimization – What are some anti-patterns I should avoid when handling in-memory data?
🔹 Error Handling & Security – How would you implement global exception handling and authorization best practices?

This API will allow users to:

• Search for event tickets (concerts, sports games, theater shows) based on location and date.
• Book a selected ticket, storing booking details in memory.
• Check the booking status, since ticket processing may take time.

Requirements & Constraints
The system should support different search types:

• EventOnly– Regular search for event tickets based on location and date.
• VIPPackage– Searches for premium experiences like VIP seating and backstage access.
• LastMinuteTickets– Special last-minute deals for events happening within the next 30 days.
• No external database – all data should be stored in-memory for now.
• Bookings take time to process, so users need to poll for status updates.
• System should be easily extendable, since new ticket types might be added later.
• The API should be built using .NET 10 with asynchronous programming in mind.
• Need to follow SOLID principles, clean code, and design patterns for scalability.

Proposed API Structure
Endpoints:

• SearchTickets(GET) – Returns available event ticket options.
• BookTicket(POST) – Stores a ticket booking with a random booking code.
• CheckBookingStatus(GET) – Returns the booking status (Pending, Success, or Failed).

Business Logic & Booking Flow

• Users search for available tickets based on location, date, and event type.
• The system fetches event ticket data from a (mock) external source.
• Users book a ticket, and the system assigns a random BookingCode.
• Ticket processing is delayed (random wait time of 30-60 seconds).
• Users check their booking status:
• VIPPackage bookings always succeed.
• EventOnly bookings succeed after processing time.
• LastMinuteTickets bookings have a higher failure rate due to limited availability.

I'm looking to improve my skills in more advanced techniques, so any guidance or feedback is greatly appreciated!