Learn how to build an API proxy server using Node.js and Express in this comprehensive tutorial. Create a server to hide public API keys, implement rate limiting, and add caching functionality. Follow along as the instructor guides you through setting up dependencies, creating a basic Express server, handling environment variables, and establishing routes. Discover techniques for making requests from the server, forwarding query parameters, and implementing essential features like rate limiting and API caching. Apply the newly created server to a client application and learn how to deploy it to Heroku, including setting up environment variables on the platform. Gain practical skills in API security and optimization through hands-on coding examples and explanations.