Building a Production-Ready .NET 8 Banking API: Clean Architecture, PostgreSQL & CI/CD on Render

Building a Production-Ready .NET 8 Banking API: Clean Architecture, PostgreSQL & CI/CD on Render There's a difference between an API that works on your machine and one that's genuinely production-ready. This article walks through both — building a Core Banking REST API in .NET 8 using Clean Architecture, then taking it all the way to a live deployment on Render with a full GitHub Actions CI/CD pipeline. We'll cover the architecture decisions, the patterns that keep the codebase maintainable, and — just as importantly — the production failures we hit and exactly how we fixed them. The Stack Layer Technology Framework ASP.NET Core 8 Web API Architecture Clean Architecture (4 layers) Messaging MediatR (CQRS pattern) Validation FluentValidation + MediatR pipeline behavior ORM Entity Framework Core 8 + Npgsql Database PostgreSQL 16 Auth JWT Bearer + token blacklist CI/CD GitHub Actions Hosting Render (Docker, Linux containers) Containerisation Docker multi-stage build Project Structure The