Mini Wallet API Backend System

I need a production-ready Web API that lets people open a digital wallet, credit or debit it, move money between wallets, and check their balance, all without ever allowing the balance to drop below zero. The stack is fixed: C#, .NET 8, ASP.NET Core, Entity Framework Core with SQL Server, organised under a Clean Architecture folder layout. Swagger should expose every endpoint for easy testing.

Security is simple and must be airtight: every call is protected by stateless JWT tokens. Because I will enforce field-level checks on the client, the server only has to reject obviously invalid or malicious requests, but it must still guarantee business rules such as “no negative balances” and “source and destination wallets exist”.

Please keep the domain logic in its own layer, repository interfaces clean, and use EF Core migrations so I can spin up the database instantly. Once finished, I expect:

• Source code in a Git-friendly structure (domain, application, infrastructure, presentation)
• SQL Server migrations committed and runnable
• Fully documented Swagger UI with example requests and responses
• Postman (or similar) collection for quick verification
• A brief README explaining setup, JWT generation, and any environment variables

If you have questions about the flow or edge cases, let me know early so we can keep iteration tight.