Securing API keys in Single Page Applications (SPAs) can be challenging due to the lack of security when embedding keys directly into the application, and the limitations of CORS. To address this issue, deploying a proxy application is recommended. This proxy intercepts requests from the SPA, appends the API key securely, and forwards the requests to the target API, such as the Yahoo! Finance API, while handling responses back to the SPA. The proxy can manage requests using HTTP methods like GET, POST, PATCH, PUT, and DELETE, with a specific focus on GET in this tutorial, employing PHP and the Zend Framework for implementation. The article also touches on the importance of implementing CORS for browser-to-API communications, as SPAs rely on this to access proxy APIs. While alternative proxy configurations using servers like Apache HTTP and nginx are possible, they are beyond the scope of this discussion. The use of proxies is a practical solution for API access in SPAs until more developers adopt OAuth2, thus avoiding the need to code APIs as server applications.