Adding a 404 Page
To create a 404 page create a page whose path matches the regex
/404*. Most often you’ll want to create a React component page at
Gatsby ensures that your 404 page is built as
404.html as many static hosting
platforms default to using this as your 404 error page. If you’re hosting your
site another way, you’ll need to setup a custom rule to serve this file for 404
When developing, Gatsby adds a default 404 page that overrides your custom 404 page. But you can still preview your 404 page by clicking “Preview custom 404 page” to verify that it’s working as expected.