API Routes vs Server Actions – When to Use What

Table of Contents

1. Introduction
2. What Are API Routes in Next.js?
3. What Are Server Actions in Next.js?
4. API Routes: When to Use Them
5. Server Actions: When to Use Them
6. Comparing API Routes and Server Actions
7. Performance Considerations
8. Security and Authentication
9. Best Practices for API Routes and Server Actions
10. Real-World Example: Choosing Between API Routes and Server Actions
11. Conclusion

1. Introduction

In modern web applications, the need for handling server-side logic efficiently is growing. In Next.js, there are two prominent ways to handle backend logic: API Routes and Server Actions. Both provide ways to run server-side code, but they serve different use cases. Understanding the differences and when to use each can help optimize your application’s performance, maintainability, and scalability.

This module will dive into the differences between API Routes and Server Actions, explore their use cases, and discuss the scenarios where one might be more beneficial than the other.

2. What Are API Routes in Next.js?

API Routes in Next.js allow you to define server-side endpoints within your Next.js app. These routes behave like traditional API endpoints, making it easy to integrate backend functionality directly into the app without needing a separate backend server.

API routes are defined inside the pages/api directory. When a request is made to a path within the api folder, Next.js triggers the corresponding handler function. API routes are ideal for handling things like CRUD operations, database queries, or third-party API interactions.

Example of an API Route:

tsxCopyEdit// pages/api/hello.ts
export default function handler(req, res) {
  res.status(200).json({ message: 'Hello from API Route' });
}

In this example, the route /api/hello returns a simple JSON response when hit with a GET request.

3. What Are Server Actions in Next.js?

Server Actions in Next.js represent a new way to perform server-side operations, introduced in Next.js 13 and above. They allow you to write server-side code in the context of React components using the App Router.

Unlike API routes, which define endpoints separately, Server Actions are defined within React components and can be executed directly from the component itself. This is particularly useful when you need to handle side effects, mutations, or data fetching on the server in response to user interactions.

Example of Server Action:

tsxCopyEdit// app/todo/page.tsx
'use server'

export async function addTodo(todo: string) {
  // logic to add todo to a database
  console.log(todo);
  return { success: true };
}

export default function TodoPage() {
  return (
    <div>
      <h1>Todo List</h1>
      <button onClick={() => addTodo('New Task')}>Add Todo</button>
    </div>
  );
}

In this example, the addTodo function is a Server Action. It’s executed directly within the component without a dedicated API endpoint.

4. API Routes: When to Use Them

API Routes are best suited for traditional backend operations such as:

• CRUD operations: Creating, reading, updating, and deleting data on the server.
• Authentication and Authorization: Handling user authentication and authorization through JWT tokens or session management.
• External API integrations: Interacting with third-party services and APIs.
• File uploads and processing: Managing file uploads (e.g., images, PDFs) or processing file data.

Use API routes when you want to have explicit, reusable endpoints that can be accessed from different parts of your app, other apps, or external services. API routes can be consumed both client-side and server-side, making them flexible and versatile.

5. Server Actions: When to Use Them

Server Actions are ideal for scenarios where:

• Server-side logic is tightly coupled with the component: Server Actions allow you to execute server-side logic directly from your React components without having to create a separate API route. This is great for situations where the action is tightly coupled with a user interface interaction.
• No need for external requests: Server Actions are best for scenarios where the logic doesn’t need to be exposed via an external endpoint.
• Immediate data changes in the component: If you need to update UI state directly after executing the server-side logic, Server Actions can simplify the process by handling both in the same context.

Server Actions are suitable for interactive workflows that involve server-side data fetching, mutations, or side effects, especially when they are integrated closely with user interactions.

6. Comparing API Routes and Server Actions

7. Performance Considerations

• API Routes: Every call to an API route is an HTTP request, which can introduce overhead. For high-frequency requests, this can result in slower response times and increased server load.
• Server Actions: Server Actions run directly on the server and are part of the component lifecycle, reducing overhead and providing faster performance. This makes them ideal for real-time, user-driven interactions where performance is crucial.

8. Security and Authentication

• API Routes: When using API routes for sensitive operations (such as authentication, database manipulation), make sure to implement proper authentication (e.g., JWT, session management) and authorization checks to protect routes.
• Server Actions: Since Server Actions are defined server-side and executed only within the component, they inherently provide a higher level of security, as there are no exposed HTTP endpoints to potentially exploit.

9. Best Practices for API Routes and Server Actions

• Use API Routes for Backend Operations: For traditional backend functionality like interacting with a database, handling external APIs, or managing file uploads, API routes are more suitable.
• Use Server Actions for UI-Related Server Logic: If the server-side logic directly affects a React component or user interaction, use Server Actions. This provides a cleaner, more declarative way of handling server-side mutations.
• Keep Logic Modular: Keep your server logic modular. For complex operations, consider splitting large functions into smaller ones, whether in API routes or Server Actions, to make them more maintainable and testable.

10. Real-World Example: Choosing Between API Routes and Server Actions

Scenario 1: CRUD Operations

If you are building a blog and need to manage posts, you would likely choose API Routes to handle CRUD operations (create, read, update, delete) via dedicated endpoints like /api/posts.

tsxCopyEdit// pages/api/posts.ts
export default async function handler(req, res) {
  if (req.method === 'POST') {
    // Create post logic
  } else if (req.method === 'GET') {
    // Fetch posts logic
  }
  res.status(200).json({ message: 'Posts fetched successfully' });
}

Scenario 2: Submitting a Form

If you’re building a form submission that involves sending data directly to the server after a user clicks “Submit”, Server Actions might be a better choice. The action is tightly coupled with the component and user interaction.

tsxCopyEdit// app/form/page.tsx
'use server'

export async function handleSubmit(formData: FormData) {
  // Handle the form submission logic here
}

export default function FormPage() {
  return (
    <form onSubmit={() => handleSubmit(formData)}>
      <button type="submit">Submit</button>
    </form>
  );
}

11. Conclusion

Both API Routes and Server Actions have their place in Next.js development. API Routes are best suited for traditional backend tasks such as CRUD operations, external API calls, and complex logic that needs to be exposed externally. On the other hand, Server Actions offer a more streamlined, performance-oriented solution for handling server-side logic directly within your React components.

By understanding the strengths and limitations of both, you can make more informed decisions on when to use each approach, ensuring your application remains efficient, secure, and maintainable.