backend-architecture-nestjs-prisma-vertical

name	backend-architecture-nestjs-prisma-vertical
description	NestJS, Prisma ORM, Vertical Slice Architecture, and Strict TypeScript for zero-hallucination backend development.

NestJS + Prisma (Vertical Slice) — "Max Power" AI Architecture

AI Context & Token Optimization (Zero-Hallucination Rules)

1. Opinionated Framework: NestJS is mandatory. Unstructured frameworks like Express are BANNED. You must use decorators (@Controller, @Injectable) and modules.
2. Vertical Slice Architecture: Do NOT use traditional layered architectures (global controllers/, services/). Group all files by feature (e.g., src/features/auth/) to localize AI context and save memory tokens.
3. Strict TypeScript & Compile-Time Safety: The any type is strictly forbidden.
4. Prisma ORM as Source of Truth: Raw SQL queries are BANNED. You must modify schema.prisma, and rely on the compiler to catch invalid database calls.
5. Validation: All incoming requests MUST be validated using DTOs with class-validator and class-transformer.

Project Structure

src/
├── main.ts                     # Application entry point
├── app.module.ts               # Root module
├── core/                       # Core infrastructure (written once)
│   ├── prisma/                 # Prisma service and module
│   ├── guards/                 # Authentication/Authorization guards
│   ├── filters/                # Global exception filters
│   └── interceptors/             # Global interceptors
└── features/                   # ⬅️ Vertical Slices (Feature Modules)
    ├── auth/
    │   ├── auth.module.ts
    │   ├── auth.controller.ts
    │   ├── auth.service.ts
    │   └── dtos/
    │       ├── login.dto.ts
    │       └── register.dto.ts
    └── users/
        ├── users.module.ts
        ├── users.controller.ts
        └── users.service.ts

Naming Conventions

Artifact	Convention	Example
Files	kebab-case with type	auth.controller.ts
Classes	PascalCase	AuthController
Methods/Variables	camelCase	registerUser
Prisma Models	PascalCase (Singular)	model User

Architectural Patterns

Dependency Injection: Use NestJS constructor injection exclusively.

Prisma Workflow:

1. Modify prisma/schema.prisma.
2. Never write migrations manually. Use CLI commands to generate them.
3. Inject PrismaService into feature services to interact with the DB. The LSP will guide you with exact types.

Global Error Handling: Do not use inline try/catch for standard HTTP errors. Throw NestJS exceptions (ConflictException, NotFoundException) and let the global filter handle the JSON formatting.

Testing Strategies

Layer	Test Type	Framework	File Naming
Feature Service	Unit	Jest + Mock Prisma	auth.service.spec.ts
Controller	Unit	Jest	auth.controller.spec.ts
Feature Endpoint	E2E	Jest + Supertest + TestDB	auth.e2e-spec.ts