Why Choose Next.js for a Backend?

While Next.js is famous for its frontend capabilities, the `App Router` has solidified its position as a powerful full-stack framework. Building your API and frontend in the same codebase simplifies deployment and allows for seamless code sharing. This guide will show you how to leverage **Route Handlers** to create a clean, organized, and scalable backend.

Setting Up the Stack

Our stack will consist of three core technologies. Here's what you need to install:

• **Next.js 15**: The framework to host our API routes.
• **TypeScript**: For robust type-checking and a better developer experience.
• **Prisma**: A modern ORM (Object-Relational Mapper) that makes database interactions intuitive and type-safe.

Prisma Schema & Database Setup

First, let's define our database schema. We'll create a simple `User` model with `id`, `email`, and `name`. This schema is the single source of truth for our database tables and models.

// prisma/schema.prismagenerator client {provider = "prisma-client-js"}datasource db {provider = "postgresql"url = env("DATABASE_URL")}model User {idInt @id @default(autoincrement())email String @uniquenameString?posts Post[]}model Post {idInt @id @default(autoincrement())title Stringcontent String?authorUser@relation(fields: [authorId], references: [id])authorId Int}

After defining the schema, run the following commands to generate the Prisma client and push the changes to your database. This will create the `User` and `Post` tables.

// prisma/schema.prismagenerator client {provider = "prisma-client-js"}datasource db {provider = "postgresql"url = env("DATABASE_URL")}model User {idInt @id @default(autoincrement())email String @uniquenameString?posts Post[]}model Post {idInt @id @default(autoincrement())title Stringcontent String?authorUser@relation(fields: [authorId], references: [id])authorId Int}

Creating a Route Handler

In the App Router, API routes are defined in a `route.ts` file inside a route segment. Let's create an endpoint to handle user-related operations. We'll put this file at `app/api/users/route.ts`.

// prisma/schema.prismagenerator client {provider = "prisma-client-js"}datasource db {provider = "postgresql"url = env("DATABASE_URL")}model User {idInt @id @default(autoincrement())email String @uniquenameString?posts Post[]}model Post {idInt @id @default(autoincrement())title Stringcontent String?authorUser@relation(fields: [authorId], references: [id])authorId Int}

This single file handles both `GET` and `POST` requests, keeping related logic co-located. This pattern promotes a clean, feature-based architecture. For more complex logic, you can abstract functions into a separate `lib/` directory.

Advanced Topics & Best Practices

Conclusion

By using Next.js Route Handlers, TypeScript, and Prisma, you can build a robust, maintainable, and highly scalable REST API without leaving your Next.js project. This approach streamlines development, leverages the framework's built-in optimizations, and provides a superior full-stack developer experience.