How to fix Error 404 on Netlify for SPAs built with Reactjs

Introduction

Hosting a React application on the Netlify platform often runs into an "Error 404". This is because an app built with Reactjs is a SPA (Single Page Application). Routing is done on the application and no HTTP calls are made to fetch pages server-side.

To fix this error,

1. go to the public folder of your application
2. create a file name _redirects( no file extension)
3. add the following content to the _redirects file:

/*    /index.html   200

1. Rebuild the application and the error is fixed.

This tells Netlify to route all redirects to the index.html which is the root entry of your application. In Firebase hosting, this is usually handled inside a config file inside the project root.