Next.js supports React Server Components (RSC) and Server Actions, enabling a shift from client-heavy interactivity to server-driven rendering and logic.
Key Topics:
What are React Server Components (RSC)?
How Server Actions replace client-side mutations
Form submissions without client-side JavaScript
Pros and cons: performance vs flexibility
Ideal Audience: Advanced React/Next.js develop
With the release of Next.js 14, the way we build full-stack web applications has fundamentally shifted. By combining React Server Components (RSC) and the new Server Actions API, developers now have a powerful pattern to reduce client-side complexity, improve performance, and deliver better user experiences.
This article unpacks these technologies, why they matter, and how to use them effectively in real-world Next.js apps.
🧩 What Are React Server Components (RSC)?
React Server Components (RSC) are a major innovation that allow components to render entirely on the server. Unlike traditional React components, they never get shipped to the browser, which means:
Zero client-side JavaScript
No hydration overhead
Faster page loads, especially on slower networks
⚙️ Example: Server vs Client Component
// This is a Server Component by default
export default async function ProductList() {
const products = await fetchProductsFromDB()
return (
<ul>
{products.map(p => <li key={p.id}>{p.name}</li>)}
</ul>
)
}
If you need interactivity like onClick, you must explicitly mark it as a client component:
‘use client’
export default function LikeButton() {
const [liked, setLiked] = useState(false)
return <button onClick={() => setLiked(!liked)}>{liked ? ‘❤️’ : ‘🤍’}</button>
}
This explicit separation keeps your bundles lean and your UI logic clean.
⚡ What Are Server Actions?
Server Actions let you define functions that execute on the server, but they are triggered directly from your components—just like client-side callbacks. They are ideal for:
Form submissions
Database writes
Email triggers
Any non-UI side effect
Instead of using fetch() or axios to call an API route, you write server logic inline using a function with ‘use server’.
✍️ Example: Submitting a form without JavaScript
// app/contact/page.tsx
export async function sendMessage(formData: FormData) {
‘use server’
const message = formData.get(‘message’)
await saveMessageToDB(message)
}
export default function ContactPage() {
return (
<form action={sendMessage}>
<textarea name=“message” required />
<button type=“submit”>Send</button>
</form>
)
}
✅ No onSubmit, no client-side JavaScript, no extra API routes needed.
🔁 How Server Actions Replace Client-Side Mutations
Before Server Actions, handling data mutations meant:
Making an API route (/api/submit)
Using fetch() inside a client component
Managing loading/error state manually
With Server Actions:
Business logic stays close to your UI
Error handling is simplified using try/catch blocks
No need to write REST endpoints unless exposing them to third parties
‘use client’
function Form() {
const action = async (formData) => {
‘use server’
await db.insertMessage(formData.get(‘message’))
}
return <form action={action}>…</form>
}
📈 Performance vs Flexibility: Trade-Offs to Know
✅ Pros
Reduced bundle size: Less JavaScript sent to the client
Simplified architecture: No need for separate API layers for internal logic
Built-in CSRF protection: Forms using Server Actions automatically include anti-CSRF measures
Improved SEO and time-to-first-byte (TTFB)
⚠️ Cons
No immediate client-side state updates: Rely on full page reload or revalidation unless manually updated
Learning curve: RSC and Server Actions require unlearning some React patterns
Limited tooling: Debugging or mocking Server Actions during development is still maturing
Not yet fully supported in all hosting environments
👥 Ideal Audience
These tools are best suited for:
Advanced React/Next.js developers
Teams building high-performance, SEO-friendly apps
Applications with frequent form submissions, mutations, or data fetching
Developers aiming for minimalist front-end bundles