useActionState vs useFormState: What’s the Difference and When to Use Each

React 18 introduced new hooks aimed at simplifying form handling in React applications, especially those leveraging server components, progressive enhancement, or async data flows. Among these are two similarly named but functionally different hooks: useActionState and useFormState.

At first glance, these hooks may appear to solve the same problem—handling form submissions—but they are designed for different use cases. Understanding the difference between them is essential to building clean, modern, and efficient forms in React or frameworks like Next.js.

In this blog, we’ll explore:

• What useActionState and useFormState are
• How each hook works
• Key differences between them
• When to use one over the other
• Practical examples to help you decide which is right for your project

What Is useActionState?

useActionState is a React hook that manages local state based on a user-triggered action—most commonly a form submission. It’s designed for client components and allows you to define an asynchronous function that processes submitted form data and returns a new state object.

Key Features:

• Accepts a reducer-like function (prevState, formData) => nextState
• Allows asynchronous logic inside the reducer function
• Returns an action function tied to the <form action={...}> attribute
• Suitable for local, client-side feedback (like success or error messages)

Basic Example:

import { useActionState } from 'react';

function ContactForm() {
  const [formState, formAction] = useActionState(async (prev, formData) => {
    const name = formData.get('name');
    if (!name) return { error: 'Name is required' };
    return { success: `Hello, ${name}!` };
  }, { error: null, success: null });

  return (
    <form action={formAction}>
      <input type="text" name="name" placeholder="Enter your name" />
      <button type="submit">Submit</button>
      {formState.error && <p style={{ color: 'red' }}>{formState.error}</p>}
      {formState.success && <p style={{ color: 'green' }}>{formState.success}</p>}
    </form>
  );
}

This hook is ideal for building forms that process client-side logic like validations, form data transformations, or async client-side actions (like sending a message via API).

What Is useFormState?

useFormState is a server-aware hook commonly used in frameworks like Next.js App Router. It’s designed for server actions and works within React’s server components. Rather than defining logic in the component, the processing happens in a separate server action, and the hook ties the result of that action to the client UI.

Key Features:

• Integrates with server actions via app/ directory in Next.js
• Accepts a server action and an initial state
• Automatically re-renders the component with updated state from the server
• Supports seamless form submission across client and server boundaries

Basic Example (Next.js App Router):

'use client';
import { useFormState } from 'react';

async function createUser(prevState: any, formData: FormData) {
  const name = formData.get('name') as string;
  if (!name) return { error: 'Name is required' };
  return { success: `Welcome, ${name}` };
}

export default function ServerForm() {
  const [formState, formAction] = useFormState(createUser, { error: null, success: null });

  return (
    <form action={formAction}>
      <input type="text" name="name" />
      <button type="submit">Submit</button>
      {formState.error && <p>{formState.error}</p>}
      {formState.success && <p>{formState.success}</p>}
    </form>
  );
}

This setup allows the form to be processed on the server while keeping UI updates reactive and fast.

Key Differences Between useActionState and useFormState

When to Use useActionState

You should use useActionState when:

• You are working in a React client component
• You want to handle form submission and feedback entirely on the client
• You don’t need to interact with a database or secure APIs directly from the server
• You want to avoid excessive boilerplate with useState or useReducer
• You are managing UI-only feedback like showing a “Thank you” message

Examples:

• Client-side form validation
• Submitting feedback via third-party APIs
• Login form that hits a public API
• Dynamic forms in dashboards and admin panels

When to Use useFormState

You should use useFormState when:

• You’re building with Next.js App Router and React Server Components
• You want the form to trigger a server-side mutation, like updating a database
• You want the result of that mutation passed back to the client automatically
• You need to securely handle logic that should not run on the client
• You want seamless integration with server actions and server routing

Examples:

• Creating or updating users in a database
• Submitting a support ticket via server-side logic
• Admin form for changing product details
• Forms that interact with protected server APIs

Performance and Security Implications

One important distinction is around security. Since useFormState processes the form server-side, it keeps sensitive logic (e.g., authentication, data access) off the client, which is more secure.

On the other hand, useActionState runs fully on the client. This makes it fast and responsive but not ideal for sensitive operations that require authentication or interaction with protected data sources.

In terms of performance, useActionState gives you immediate feedback without a round trip to the server. However, useFormState can be optimized on the server using streaming and caching, especially in production deployments using edge runtimes like Vercel.

Can You Use Both in One Project?

Yes—absolutely. In fact, many modern projects use both. Here’s how:

• Use useFormState for server-sensitive actions (e.g., database, authentication).
• Use useActionState for client-only feedback or UI interaction (e.g., popups, alerts, async local behavior).

This hybrid approach helps you balance performance and security based on context.

Conclusion

React 18 brought new capabilities for form handling through hooks like useActionState and useFormState. While both hooks allow you to simplify and structure your form logic, they serve different purposes and are optimized for different environments.

• Use useActionState for local, client-side form interactions.
• Use useFormState for server-driven logic where secure, persistent actions are required.

Understanding when and how to use each hook will make your forms cleaner, safer, and more aligned with modern React architecture—especially in server-aware environments like Next.js.

By choosing the right hook for the job, you’ll write less boilerplate, create more predictable forms, and deliver a better user experience.