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tRPC End-to-End Type Safe APIs · Lesson

Server Components and tRPC Data Fetching

Understand how to fetch data directly in Next.js Server Components using tRPC for optimal performance.

Server Components and tRPC Data Fetching is a free tRPC End-to-End Type Safe APIs lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the tRPC End-to-End Type Safe APIs learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Intro to Server Components

Welcome! In Next.js, Server Components (SCs) are a powerful feature that lets you render parts of your UI directly on the server.

This means less JavaScript sent to the browser, faster initial page loads, and improved SEO!

Data Fetching on the Server

A key benefit of Server Components is their ability to fetch data directly on the server. Unlike Client Components, SCs don't need to make API calls from the browser.

This allows data to be fetched and rendered before the page is even sent to the client, boosting performance.

tRPC's Role in SCs

This is where tRPC shines! When used in Server Components, tRPC allows you to call your backend procedures directly, without any HTTP overhead.

It's like importing a local function, but with end-to-end type safety guaranteed by tRPC and TypeScript.

Build a Server-Side Caller

To fetch data in Server Components, we need a special tRPC client that calls procedures directly, bypassing HTTP. This is often called a "server-side caller" or "server client."

It uses your tRPC router directly to ensure type safety without network overhead. Here's a simplified example:

import { appRouter } from '@/server/routers/_app';
import { createCallerFactory } from '@trpc/server';

// Create a tRPC caller that can be used on the server
const createCaller = createCallerFactory(appRouter);

export const serverClient = createCaller({});
// Context can be passed here, e.g., createCaller({ user: currentUser })

Fetching Data in an SC

Now, let's use our serverClient to fetch data directly within a Next.js Server Component. Notice how it looks just like calling a local function!

The data is fetched on the server before the component is rendered and sent to the client.

// app/page.tsx (Server Component)
import { serverClient } from '@/utils/trpc';

export default async function HomePage() {
  const posts = await serverClient.post.list(); // Call a tRPC query

  return (
    <div>
      <h1>Latest Posts</h1>
      <ul>
        {posts.map(post => (
          <li key={post.id}>{post.title}</li>
        ))}
      </ul>
    </div>
  );
}

SC Data to Client Components

Server Components often fetch data, but UI interactions happen in Client Components. You can pass the fetched data as props from an SC to a CC.

Remember to mark client components with "use client" at the top.

// components/PostList.tsx (Client Component)
"use client";

interface Post {
  id: string;
  title: string;
}

export function PostList({ posts }: { posts: Post[] }) {
  // Client-side interactions can happen here
  return (
    <ul>
      {posts.map(post => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  );
}

// app/page.tsx (Server Component, updated)
import { serverClient } from '@/utils/trpc';
import { PostList } from '@/components/PostList';

export default async function HomePage() {
  const posts = await serverClient.post.list();

  return (
    <div>
      <h1>Latest Posts</h1>
      <PostList posts={posts} /> {/* Pass data as props */}
    </div>
  );
}

Queries with Input Parameters

Just like regular tRPC queries, you can pass input parameters to your server-side tRPC calls. This is useful for fetching specific data based on URL parameters or other server-side logic.

// app/posts/[id]/page.tsx (Server Component)
import { serverClient } from '@/utils/trpc';

interface PostPageProps {
  params: { id: string };
}

export default async function PostPage({ params }: PostPageProps) {
  const { id } = params;
  const post = await serverClient.post.byId({ id }); // Pass 'id' as input

  if (!post) {
    return <div>Post not found!</div>;
  }

  return (
    <div>
      <h1>{post.title}</h1>
      <p>{post.content}</p>
    </div>
  );
}

Graceful Error Handling

Errors thrown by your tRPC procedures on the server will propagate up to the Server Component. You can use standard JavaScript try...catch blocks to handle them.

This ensures your application remains robust even if data fetching fails.

// app/page.tsx (Server Component with error handling)
import { serverClient } from '@/utils/trpc';

export default async function HomePage() {
  let posts = [];
  let error = null;

  try {
    posts = await serverClient.post.list();
  } catch (e) {
    console.error("Failed to fetch posts:", e);
    error = "Could not load posts. Please try again.";
  }

  return (
    <div>
      <h1>Latest Posts</h1>
      {error && <p style={{ color: 'red' }}>{error}</p>}
      <ul>
        {posts.map(post => (
          <li key={post.id}>{post.title}</li>
        ))}
      </ul>
    </div>
  );
}

SC vs. CC Data Fetching

When should you use Server Components for data fetching versus Client Components (e.g., with React Query)?

  • Server Components: Ideal for initial data, SEO, static/server-rendered content, and reducing client bundle size.
  • Client Components: Best for interactive data, real-time updates, user-specific data after initial load, and mutations.

Often, you'll use a mix of both!

Server Component Data Fetch

Consider a Next.js App Router project using tRPC. You need to display a list of products on the initial page load, which should be fast and SEO-friendly.

Recap: SCs & tRPC

In this lesson, we explored fetching data directly within Next.js Server Components using tRPC.

  • We learned to create a server-side tRPC caller.
  • Fetched data directly in Server Components.
  • Passed fetched data as props to Client Components.
  • Handled query parameters and errors in SCs.
  • Understood the distinction between SC and CC data fetching.

This approach combines tRPC's type safety with Server Components' performance benefits for robust and efficient data fetching.

Frequently asked questions

Is the “Server Components and tRPC Data Fetching” lesson free?

Yes — the full text of “Server Components and tRPC Data Fetching” is free to read here on the web, and the tRPC End-to-End Type Safe APIs course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the tRPC End-to-End Type Safe APIs course, upgrade to CoddyKit PRO.

What will I learn in “Server Components and tRPC Data Fetching”?

Understand how to fetch data directly in Next.js Server Components using tRPC for optimal performance. You practise tRPC End-to-End Type Safe APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start tRPC End-to-End Type Safe APIs?

No prior experience is required. tRPC End-to-End Type Safe APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Server Components and tRPC Data Fetching” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this tRPC End-to-End Type Safe APIs lesson?

Yes. Every tRPC End-to-End Type Safe APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. tRPC with Next.js App Router
  2. Advanced React Query Integration
  3. Server Components and tRPC Data Fetching
  4. Optimistic Updates with tRPC Mutations
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