Here is a 1-paragraph summary of the text: To improve the performance and efficiency of Angular web applications that use server-side rendering for search engine optimization, two techniques can be employed: using TransferState to limit calls made to potentially slow APIs and implementing a watchdog mechanism to abandon long-running API calls. The TransferState service allows developers to store responses from API calls on the Node.js server and retrieve them in the browser, reducing the number of requests made to slow APIs. Meanwhile, the watchdog mechanism uses a timer to wait for API responses before sending partially rendered HTML to the browser, allowing it to continue rendering the view while waiting for the response. By implementing these techniques, developers can improve the performance and efficiency of their Angular applications, increasing user satisfaction and search engine ranking.