Nextjs Custom Error Pages Step by step Implementation and Top 10 Questions and Answers
 .NET School AI Teacher - SELECT ANY TEXT TO EXPLANATION.    Last Update: April 01, 2025      15 mins read      Difficulty-Level: beginner

Explaining Next.js Custom Error Pages in Detail

Next.js, a popular React framework for server-side rendering (SSR) and generating static site applications (SSG), offers robust error handling mechanisms. One of these mechanisms allows developers to create custom error pages to enhance user experience during runtime errors, build-time errors, and 404 errors.

Overview of Next.js Error Pages

Next.js predefines error pages for different error conditions, such as 500 Internal Server Error and 404 Not Found. However, these default pages may not align with the overall branding and aesthetic of your application. Custom error pages offer an opportunity to display more relevant and user-friendly error content, improving the user experience.

Importance of Custom Error Pages

  1. Enhanced User Experience: Customized error pages can provide a more user-friendly and engaging experience. By using your brand's design elements, such as colors, fonts, and images, error pages can help maintain brand continuity despite an unexpected issue.

  2. User Retention: Proper handling of errors can prevent users from abandoning your site. Tailored error messages can guide users to the correct page or help them resolve the issue, increasing the likelihood of user retention.

  3. Improved Debugging: When errors occur during the development or production phase, custom error pages can provide useful debugging information without exposing sensitive server details to end-users.

  4. SEO Benefits: Having a custom 404 page can inform search engines that a page doesn't exist and suggest alternative pages. This helps avoid broken links and can improve your site's SEO performance.

  5. Accessibility: Custom error pages can be designed to comply with web accessibility standards, ensuring that all users, including those with disabilities, can understand and navigate through them.

Creating a Custom 404 Page

To create a custom 404 page in Next.js, simply create a file named 404.js in the pages folder. This file should export a React component that represents your custom 404 page.

// pages/404.js
import Head from 'next/head';

const FourZeroFour = () => (
  <>
    <Head>
      <title>Oops! Page not found</title>
    </Head>
    <div className="error-container">
      <h1>404 - That page does not seem to exist!</h1>
      <p>Let's find it for you.</p>
      <a href="/">Return to the homepage</a>
    </div>
    <style jsx>{`
      .error-container {
        text-align: center;
        margin-top: 50px;
      }
      h1 {
        font-size: 2rem;
        margin-bottom: 20px;
      }
      p {
        font-size: 1.2rem;
        margin-bottom: 10px;
      }
      a {
        text-decoration: none;
        color: blue;
      }
    `}</style>
  </>
);

export default FourZeroFour;

Explanation:

  • Head Component: The Head component from Next.js allows you to set the page title dynamically.
  • Error Container: A simple div container to hold our error message and link.
  • Routing Link: An anchor tag linking back to the homepage.
  • CSS Styling: Inline CSS to style the error page, keeping it simple and focused on delivering the message.

Creating a Custom 500 Server Error Page

Custom 500 server error pages are created in a similar manner by creating a file named 500.js in the pages folder.

// pages/500.js
import Head from 'next/head';

const ServerError = () => (
  <>
    <Head>
      <title>Server Error</title>
    </Head>
    <div className="server-error">
      <h1>500 - Internal Server Error</h1>
      <p>Oops, something went wrong on our end! Please try again later.</p>
    </div>
    <style jsx>{`
      .server-error {
        text-align: center;
        margin-top: 50px;
      }
      h1 {
        font-size: 2rem;
        margin-bottom: 20px;
      }
      p {
        font-size: 1.2rem;
      }
    `}</style>
  </>
);

export default ServerError;

Explanation:

  • Head Component: Again, setting the page title dynamically.
  • Server Error Information: A div container with a message to inform users about the server error.
  • CSS Styling: Inline CSS to style the error page, directing visitors to wait and try again later.

Custom Error Pages during Development

During development, Next.js renders custom error pages on the server because it provides more detailed error messages for debugging. However, when running in production, the error pages are pre-rendered.

Important Considerations

  1. Error Boundaries: For handling errors within specific components, you can use React's Error Boundaries. They are a special class of React components that catch JavaScript errors anywhere in their child component tree, log those errors, and display a fallback UI.

  2. Global Error Handling: Next.js incorporates the _error.js file for handling global errors. While it's less common and somewhat outdated, it can be useful for capturing and logging errors at the highest level.

  3. User Feedback: Ensure that your custom error pages have clear descriptions and options for users to navigate back to safety or report the issue.

In conclusion, custom error pages in Next.js are a critical part of creating a seamless and user-friendly application. By providing error pages that reflect your brand and offer helpful guidance, you can improve the overall user experience and maintain a positive relationship with your users.




Step-by-Step Guide to Custom Error Pages in Next.js for Beginners

Creating custom error pages in Next.js can greatly improve the user experience on your application by handling errors gracefully and providing meaningful feedback. Let’s walk you through the process from setting up the route to running the application and understanding the data flow.

Step 1: Setting Up Your Next.js Application

First off, ensure you have Node.js and npm installed on your system. If not, download and install them from nodejs.org.

Create a New Next.js Project

Run the following command in your terminal:

npx create-next-app@latest custom-error-pages-app

Navigate into your project directory:

cd custom-error-pages-app

Step 2: Creating Custom Error Pages

Next.js uses the file system as its API for routing. To create custom error pages, you need to add a specific file in your project structure.

Create 404 Page

The 404 page is displayed when the user navigates to a non-existent page. Create the following file:

pages/404.js

Add some basic content inside this file:

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

Create 500 Page

The 500 page is used for displaying internal server errors. Create the following file:

pages/_error.js

And include some content:

// pages/_error.js
import { useEffect } from "react";

function Error({ statusCode }) {
  useEffect(() => {
    // Log the status code or handle it
    console.log(`Error occurred on page with status: ${statusCode}`);
  }, [statusCode]);

  return <h1>{statusCode ? `Error ${statusCode}` : `Error`}</h1>;
}

Error.getInitialProps = ({ res, err }) => {
  const statusCode = res ? res.statusCode : err ? err.statusCode : 404;
  return { statusCode };
};

export default Error;

Step 3: Setting Up Routes

Creating custom error pages doesn’t require additional routing, as Next.js automatically routes errors to your custom pages. However, you can manually trigger a 404 error to test the custom 404 page by visiting a non-existent route.

For testing the 500 page, you can deliberately throw an error in your application like so:

// pages/about.js
export default function About() {
  useEffect(() => {
    throw new Error("Internal Server Error");
  }, []);

  return <h1>About Page</h1>;
}

Step 4: Running the Application

Now it's time to run our Next.js application and see our custom error pages in action.

Start the development server:

npm run dev

Visit http://localhost:3000/nonexistent-route to see the custom 404 page.

Visit http://localhost:3000/about to deliberately trigger the 500 page and see your custom error handling in action.

Step 5: Understanding the Data Flow

Let's break down how the data flows throughout this process.

404 Page

  1. User Navigation: The user navigates to a route that does not exist.
  2. Route Handling: Next.js detects that the requested route does not match any pages in the pages directory.
  3. Custom 404 Page Rendering: Next.js renders the pages/404.js file.
  4. Page Display: The user sees the custom 404 page you created.

500 Page

  1. Server Error: An error occurs on the server-side, such as an exception being thrown in a component.
  2. Error Handling: The Error component defined in pages/_error.js is invoked.
  3. Initial Props: Error.getInitialProps is called, where you can customize what data is passed to the Error component. In this case, it retrieves the status code if available.
  4. Component Rendering: The Error component renders the specified JSX based on the status code or a generic error message.
  5. Error Display: The user sees the custom 500 page you created.

Step 6: Customizing Your Error Pages

You can add more design or functionality to your custom error pages. For example, you could include a link back to the home page, a custom logo, or even an apology message.

// pages/404.js
import Link from "next/link";

export default function Custom404() {
  return (
    <>
      <h1>404 - Page Not Found</h1>
      <p>
        Oops, looks like you've navigated to a page that doesn’t exist.
        <Link href="/">
          <a>Go back to the homepage</a>
        </Link>
      </p>
    </>
  );
}

Conclusion

By setting up custom error pages in Next.js, you can enhance the user experience of your application by providing better error handling and feedback. This ensures that unexpected errors do not leave your users feeling puzzled or frustrated. With a bit of effort, you can make your application more robust and user-friendly. Happy coding!




Top 10 Questions and Answers on Next.js Custom Error Pages

Next.js, a popular React framework, provides a powerful set of tools to help developers build server-side rendered and statically generated web applications. One of its less understood features, especially by beginners, is the capability to create custom error pages. Here are the top ten questions to help you navigate this aspect of Next.js effectively.

1. What are Custom Error Pages in Next.js?

Custom error pages in Next.js allow you to define your own response for error conditions, such as 404 Not Found or 500 Internal Server Error, making your application's error handling more user-friendly and tailored to your design preferences.

2. How can I create a custom 404 page in Next.js?

Creating a custom 404 page in Next.js is straightforward. Simply create a file named 404.js inside the pages directory. This file will automatically be used as the 404 page.

Example:

// pages/404.js
export default function Custom404() {
  return <h1>Oops! You seem to be lost. Check the URL or try again later.</h1>;
}

3. Can I create a custom 500 page in Next.js?

Absolutely! Just like the 404 page, to create a custom 500 server error page, simply create a file named 500.js inside the pages directory.

Example:

// pages/500.js
export default function Custom500() {
  return <h1>Internal Server Error</h1>;
}

4. How can I use dynamic routing for custom error pages?

Next.js does not support dynamic routing within the 404.js or 500.js files directly, as they are reserved for specific error codes. However, you can handle dynamic content within the error pages by leveraging context or global states.

5. Can I apply styles to a custom error page?

Yes, you can style a custom error page using CSS or CSS-in-JS solutions like styled-components or emotion. You can also import global styles that will apply to all pages, including error pages.

Example using styled-components:

// pages/404.js
import styled from 'styled-components';

const Styled404 = styled.div`
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
`;

export default function Custom404() {
  return (
    <Styled404>
      <h1>404 - Page Not Found</h1>
    </Styled404>
  );
}

6. How can I test custom error pages locally?

To test your custom error pages locally, you can use a few strategies. For 404 pages, you can simply navigate to a non-existent route in your development server, like http://localhost:3000/nonexistent. For 500 errors, you can simulate a server error by modifying your API endpoints to throw an error deliberately.

7. What are the best practices for custom error pages?

Best practices include making sure your error pages are user-friendly, helpful, and maintain brand consistency. Include links to help users navigate back to the homepage or other important sections. Additionally, ensure that your error pages are SEO-friendly and accessible to assistive technologies.

8. Can custom error pages affect SEO?

Yes, custom error pages can impact your site's SEO, particularly 404 and 500 pages. A well-designed 404 page with clear navigation links can improve the user experience and reduce bounce rates. A 500 page, while less ideal, should clearly indicate that there is an issue and provide a way to proceed, like refreshing or trying a different page.

9. How do I redirect to a custom error page programmatically?

You can programmatically redirect to a custom error page using the next/router in React components. This is particularly useful in cases where server-side validation fails and you need to redirect the user to a specific error page.

Example:

import { useRouter } from 'next/router';

function MyComponent() {
  const router = useRouter();

  const handleButtonClick = () => {
    // conditionally redirect to 500 page
    router.push('/500');
  };

  return (
    <button onClick={handleButtonClick}>Simulate an Error</button>
  );
}

10. Can I use getInitialProps or getServerSideProps in custom error pages?

Yes, you can use getInitialProps in custom error pages (404.js and 500.js) but not getServerSideProps. This allows you to fetch additional data when the error occurs, which can be useful for logging errors, fetching error messages, or displaying them in a user-friendly manner.

Example using getInitialProps:

// pages/500.js
function Custom500({ statusCode, message }) {
  return (
    <div>
      <h1>Status Code: {statusCode}</h1>
      <p>{message}</p>
    </div>
  );
}

Custom500.getInitialProps = async ({ res, err }) => {
  return {
    statusCode: res ? res.statusCode : err ? err.statusCode : 404,
    message: "Internal Server Error. Please try again later.",
  };
};

export default Custom500;

By understanding and utilizing custom error pages effectively, you can significantly improve the user experience and make your application more robust and professional.