Server Actions vs Route Handlers in Next.js

Next.js gives us more than one way to run server-side code. Two options that come up often are Server Actions and Route Handlers.

At first, they can feel like two different ways to solve the same problem. Both can talk to a database, read environment variables, validate data, and call external APIs. But I do not use them interchangeably.

In this post, I will explain how I think about Server Actions and Route Handlers in my own Next.js projects.

What are Server Actions?

Server Actions are server-side functions that can be called from your application without manually creating an HTTP endpoint for every mutation.

A simple example looks like this:

'use server';

export async function createProject(formData: FormData) {
  const name = formData.get('name');

  // validate data
  // write to database
  // revalidate page
}

They are especially useful when the action is tightly connected to your UI.

For example:

• Creating a record from a form
• Updating a profile
• Deleting an item
• Saving settings
• Revalidating a page after a mutation

I like Server Actions because they remove some boilerplate. I do not need to create a separate API route, call it with fetch, parse the response, and then manually connect everything together.

What are Route Handlers?

Route Handlers are HTTP endpoints inside the App Router.

For example:

export async function POST(request: Request) {
  const body = await request.json();

  return Response.json({
    success: true,
    body,
  });
}

They live inside paths such as:

app/api/projects/route.ts
app/api/webhooks/route.ts

I use Route Handlers when the server logic needs to behave like a real API.

That includes:

• Webhooks
• Public API endpoints
• Requests from another application
• Mobile clients
• External integrations
• Endpoints that need custom HTTP headers or status codes

The rule I use

My simple rule is:

If the operation belongs directly to my Next.js UI, I consider a Server Action first.

If something outside the UI needs to call it, I use a Route Handler.

That rule is not perfect, but it keeps the architecture easy to understand.

Example: Creating a dashboard item

Imagine I have a dashboard form for creating a project.

I can use a Server Action:

<form action={createProject}>
  <input name="name" />
  <button type="submit">Create project</button>
</form>

The form and mutation are part of the same application. There is no strong reason to expose a public endpoint.

Now imagine Stripe, GitHub, or another service needs to send an event to my application.

That should be a Route Handler:

export async function POST(request: Request) {
  const payload = await request.text();

  // verify webhook
  // process event

  return new Response('ok');
}

A Server Action would not be the right abstraction because an external service needs a normal HTTP URL.

Validation still matters

Whichever option I use, I do not trust client input.

I normally validate data with Zod before writing anything to the database.

const projectSchema = z.object({
  name: z.string().min(2).max(80),
});

Server Actions reduce boilerplate, but they do not remove the need for validation, authorization, rate limiting, or proper error handling.

When I still prefer a Route Handler inside my own app

Sometimes I use a Route Handler even when only my own frontend calls it.

A few reasons:

• I want the endpoint to be reusable later
• I need streaming
• I need a specific HTTP response
• I am integrating with a client that already expects REST-like endpoints
• I want a clear network boundary between frontend and backend logic

There is nothing wrong with that. I care more about consistency than forcing every mutation into the newest Next.js feature.

My approach

For new Next.js applications, I usually start with Server Actions for simple dashboard mutations and forms.

I use Route Handlers for integrations, webhooks, public APIs, email endpoints, and anything that should have a normal HTTP contract.

Both are useful. The important part is understanding what boundary you are building.

Server Actions are great when the server operation is part of your React application.

Route Handlers are great when the server operation is part of your application's HTTP interface.

Once I started thinking about them that way, choosing between the two became much easier.