Configure nginx for Gatsby 404 error page

During Gatsby page development, when you hit a page that doesn't exist, you encounter a screen similar to the one below.

If you created a custom 404 page, for example in src/pages/404.js, you can click the Preview custom 404 page to display it. Entering the /404 route will do the job as well.

In production, however, the 404 page doesn't get handled by itself unless you use a dedicated hosting service for Gatsby pages. That's because Gatsby's development server is no longer present. The production bundle is just a bunch of static files. Making use of a web server (like nginx) to serve the production page forces you to configure the error pages yourself.

Disclaimer: the following nginx configuration is pretty basic, don't use it in production.

Let's assume your blog is hosted on the personalblog.com domain and is served from the /var/www/blog directory on port 80.

server {
        listen 80;
        root /var/www/blog;
        server_name personalblog.com www.personalblog.com;
        location / {
                try_files $uri $uri/ =404;
        }
}

After entering a route that doesn't exist in your production Gatsby site, nginx displays its default 404 error page.

Adding the error_page 404 /404; line makes nginx redirect to the /404 route in case of a 404 error. Your custom Gatsby 404 page will be displayed.

server {
        listen 80;
        root /var/www/blog;
        server_name personalblog.com www.personalblog.com;
        error_page 404 /404;
        location / {
                try_files $uri $uri/ =404;
        }
}

Visit the error_page docs section to explore the rest of the configuration options.