Remix Run vs. Next.js: A Clear Comparison For Developers

Choosing the right framework can make all the difference in your project. In the React world, Remix Run and Next.js are two giants. Both can build server rendered React apps but approach web development differently.

This blog goes deep on how Remix Run and Next.js handle server-side rendering, data fetching, routing etc to help you decide for your next project.

Understanding the Foundations

Server-Side Rendering Core Principles

Both Remix Run and Next.js prioritize server-side rendering to deliver faster initial page loads and improved SEO. When a request comes in, the server side code processes the request, fetches data, and sends the initial HTML to the user's browser before any client-side JavaScript executes.

Server-side rendering (SSR) enables search engines to crawl fully rendered content, improving SEO performance. It also provides users with viewable content more quickly, enhancing perceived performance.

Static Site Generation vs. Dynamic Rendering

Next.js offers flexible rendering strategies including static site generation (SSG) for content that changes infrequently. With static site generation, pages are pre-rendered at build time, generating static HTML pages that can be cached and served from a CDN.

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// Next.js static site generation example
export async function getStaticProps() {
  const res = await fetch('https://api.example.com/data')
  const data = await res.json()

  return {
    props: { data },
    // Re-generate at most once per day
    revalidate: 86400
  }
}

Remix, in contrast, focuses primarily on dynamic server-side rendering but can be configured to cache responses for static and dynamic content using HTTP caching headers.

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// Remix example with caching headers
export function headers() {
  return {
    "Cache-Control": "max-age=300, s-maxage=3600"
  };
}

export async function loader() {
  const data = await fetchData();
  return json(data);
}

Data Fetching Approaches

Next.js Data Fetching Methods

Next.js provides several approaches for data fetching, depending on when and how you need to fetch data:

1. getServerSideProps - For server side data fetching on each request

2. getStaticProps - For static site generation (SSG)

3. getStaticPaths - For dynamic routes with static generation

4. React Server Components - For component-level server-side data fetching

5. Client-side data fetching with SWR or React Query

Here's how server-side rendering with data fetching works in Next.js:

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// Server-side rendering with data in Next.js
export async function getServerSideProps(context) {
  const res = await fetch(`https://api.example.com/posts/${context.params.id}`)
  const post = await res.json()

  return {
    props: { post }
  }
}

export default function Post({ post }) {
  return (
    <article>
      <h1>{post.title}</h1>
      <div>{post.content}</div>
    </article>
  )
}

Next.js 13+ introduced a new app directory structure with built-in support for React Server Components, allowing for more granular server-side rendering and data fetching at the component level.

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// React Server Components in Next.js app directory
async function PostDetails({ id }) {
  // This runs on the server
  const post = await fetch(`https://api.example.com/posts/${id}`).then(r => r.json())

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

Remix Data Loading Pattern

Remix takes a different approach to data fetching, using a loader function defined alongside route components. This centralizes the data fetching logic for each route.

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// Remix data loading example
import { json, useLoaderData } from "remix";

export async function loader({ params }) {
  const response = await fetch(`https://api.example.com/posts/${params.id}`);

  if (!response.ok) {
    throw new Response("Not Found", { status: 404 });
  }

  return json(await response.json());
}

export default function Post() {
  const post = useLoaderData();

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

The useLoaderData hook provides type-safe access to the loader data on both the server side and client side.

Handling Data Mutations

Remix Form Handling

One of Remix's standout features is its approach to form submissions and data mutations. Remix embraces and enhances HTML forms, providing a progressive enhancement approach:

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// Remix form handling and data mutations
import { Form, useActionData, redirect } from "remix";

export async function action({ request }) {
  const formData = await request.formData();
  const title = formData.get("title");
  const content = formData.get("content");

  const errors = {};
  if (!title) errors.title = "Title is required";
  if (!content) errors.content = "Content is required";

  if (Object.keys(errors).length) {
    return json(errors);
  }

  await createPost({ title, content });
  return redirect("/posts");
}

export default function NewPost() {
  const errors = useActionData();

  return (
    <Form method="post">
      <div>
        <label>
          Title:
          <input name="title" type="text" />
        </label>
        {errors?.title && <p>{errors.title}</p>}
      </div>

      <div>
        <label>
          Content:
          <textarea name="content" />
        </label>
        {errors?.content && <p>{errors.content}</p>}
      </div>

      <button type="submit">Create Post</button>
    </Form>
  );
}

This approach works without JavaScript enabled but progressively enhances the experience when JavaScript is available. Form submission seamlessly integrates with data mutations, and Remix automatically handles loading states, error handling, and optimistic UI updates.

Next.js API Routes

Next.js handles data mutations primarily through API routes and client-side fetch calls:

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// Next.js API route for data mutation
// pages/api/posts.js
export default async function handler(req, res) {
  if (req.method === 'POST') {
    try {
      const { title, content } = req.body;

      if (!title || !content) {
        return res.status(400).json({ error: 'Missing required fields' });
      }

      const post = await createPost({ title, content });
      return res.status(201).json(post);
    } catch (error) {
      return res.status(500).json({ error: error.message });
    }
  }

  return res.status(405).json({ error: 'Method not allowed' });
}

// Form component
function CreatePostForm() {
  const [title, setTitle] = useState('');
  const [content, setContent] = useState('');
  const [errors, setErrors] = useState({});
  const router = useRouter();

  async function handleSubmit(e) {
    e.preventDefault();

    // Validate
    const validationErrors = {};
    if (!title) validationErrors.title = 'Title is required';
    if (!content) validationErrors.content = 'Content is required';

    if (Object.keys(validationErrors).length > 0) {
      setErrors(validationErrors);
      return;
    }

    try {
      const response = await fetch('/api/posts', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ title, content }),
      });

      if (!response.ok) {
        const error = await response.json();
        throw new Error(error.error || 'Failed to create post');
      }

      router.push('/posts');
    } catch (error) {
      console.error(error);
    }
  }

  return (
    <form onSubmit={handleSubmit}>
      {/* Form fields */}
    </form>
  );
}

In Next.js, API routes make the backend server capabilities available to client-side code while keeping the route publicly accessible as an HTTP endpoint.

Routing Systems

Next.js Routing

Next.js uses a file-based routing system where files in the pages directory (or app directory in Next.js 13+) automatically become routes. This approach is intuitive and straightforward:

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pages/
├── index.js         # Route: /
├── about.js         # Route: /about
├── posts/
│   ├── index.js     # Route: /posts
│   └── [id].js      # Route: /posts/:id (dynamic route)

With Next.js 13's app directory, routing becomes more feature-rich:

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app/
├── page.js          # Route: /
├── about/
│   └── page.js      # Route: /about
├── posts/
│   ├── page.js      # Route: /posts
│   └── [id]/
│       └── page.js  # Route: /posts/:id

Remix Routing

Remix also employs a file-based routing system but adds support for nested routes with layout sharing and parallel data loading:

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app/
├── routes/
│   ├── _index.jsx         # Route: /
│   ├── about.jsx          # Route: /about
│   ├── posts.jsx          # Route: /posts (layout)
│   ├── posts._index.jsx   # Route: /posts (nested index)
│   ├── posts.$id.jsx      # Route: /posts/:id
│   └── posts.new.jsx      # Route: /posts/new

Nested routes in Remix allow for shared layouts and parallel data loading, which can significantly improve the user experience by maintaining context during navigation.

Error Handling

Remix Error Handling

Remix provides a robust error-handling system with error boundaries at different levels:

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// Root error boundary in Remix
export function ErrorBoundary({ error }) {
  console.error(error);
  return (
    <html>
      <head>
        <title>Oh no!</title>
      </head>
      <body>
        <h1>Error</h1>
        <p>{error.message}</p>
        <p>The stack trace is:</p>
        <pre>{error.stack}</pre>
      </body>
    </html>
  );
}

// Route-level error boundary
export function ErrorBoundary() {
  const error = useRouteError();

  if (isRouteErrorResponse(error)) {
    return (
      <div>
        <h1>
          {error.status} {error.statusText}
        </h1>
        <p>{error.data}</p>
      </div>
    );
  }

  return (
    <div>
      <h1>Error</h1>
      <p>{error.message || 'Unknown error'}</p>
    </div>
  );
}

This approach to error handling allows developers to manage errors at various levels of the application, providing appropriate feedback to users.

Next.js Error Handling

Next.js offers several ways to handle errors:

1. Custom error pages:

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// pages/404.js
export default function Custom404() {
  return <h1>404 - Page Not Found</h1>
}

// pages/500.js
export default function Custom500() {
  return <h1>500 - Server-Side Error Occurred</h1>
}

2. Error boundary components:

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import { Component } from 'react'

class ErrorBoundary extends Component {
  constructor(props) {
    super(props)
    this.state = { hasError: false }
  }

  static getDerivedStateFromError(error) {
    return { hasError: true }
  }

  componentDidCatch(error, errorInfo) {
    console.error(error, errorInfo)
  }

  render() {
    if (this.state.hasError) {
      return <h1>Something went wrong.</h1>
    }

    return this.props.children
  }
}

export default ErrorBoundary

3. API route error handling:

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export default function handler(req, res) {
  try {
    // Process request
  } catch (error) {
    res.status(500).json({ error: 'Failed to process request' })
  }
}

Performance Considerations

Data Fetching and Caching

Next.js excels at static site generation, which can significantly improve performance for content that doesn't change frequently. It also provides granular control over caching and revalidating behavior with features like Incremental Static Regeneration (ISR).

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// Next.js ISR example
export async function getStaticProps() {
  const posts = await fetch('https://api.example.com/posts').then(r => r.json())

  return {
    props: {
      posts,
    },
    // Revalidate every 10 minutes
    revalidate: 600,
  }
}

Remix focuses on dynamic server-side rendering but leverages the browser's native fetch web API and HTTP caching mechanisms:

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// Remix with HTTP caching
export function headers() {
  return {
    "Cache-Control": "max-age=300, s-maxage=3600, stale-while-revalidate=86400"
  };
}

Server Load and Scaling

For high-traffic sites, server load is an important consideration. Next.js with static site generation can offload much of the server work to the build process, reducing server load during runtime.

Remix optimizes server load by:

1. Using HTTP caching effectively

2. Streaming server-side rendering

3. Enabling parallel data fetching for nested routes

Both frameworks support edge deployment models that can improve global performance.

Development Experience

Next.js Developer Experience

Next.js provides a streamlined development process with features like:

1. Fast Refresh for instantaneous feedback

2. Built-in image optimization

3. Automatic code splitting

4. Extensive plugin ecosystem

5. TypeScript support out of the box

Remix Developer Experience

Remix focuses on web standards and offers:

1. Nested routing with shared layouts

2. Form abstraction with progressive enhancement

3. Error boundaries at multiple levels

4. Strong loader and action pattern for data handling

5. Built-in TypeScript support

Making the Decision: When to Choose Each Framework

Choose Next.js When:

• Your project requires static site generation for content-heavy sites

• You need flexible rendering strategies

• You want to use React Server Components for granular server/client rendering

• You prefer a larger ecosystem with extensive documentation

• You're building a content-focused website with blog posts, marketing pages, etc.

Choose Remix When:

• You're building highly interactive applications with frequent data mutations

• Form handling is central to your application

• You need nested routes with parallel data loading

• You prefer working with web standards and progressive enhancement

• Error handling is crucial for your application

• You're building web apps that require real-time updates and frequent user interactions

Making the Right Choice!

Both Remix Run and Next.js help developers build fast and interactive React applications. The best choice depends on the project's needs, team skills, and how the app handles data.

Next.js offers multiple rendering options, making it a solid pick for content-heavy sites with fewer updates. On the other hand, Remix focuses on smooth server-side rendering, making it great for apps that require frequent data updates and advanced form handling.

Each framework has strengths, so it comes down to what fits best. No matter which one is chosen, both support high-performance and SEO-friendly development.