1. Server rendered pages are not optional

   Server rendering is not about SEO, it’s about performance. Consider the additional roundtrips to get scripts, styles, and subsequent API requests. In the future, consider HTTP 2.0 “pushing” of resources.
   

2. Act immediately on user input

   JavaScript allows us to mask network latency altogether. Applying this as a design principle should even remove most spinners or “loading” messages from your applications. PJAX or TurboLinks miss out on opportunities to improve the perception of speed.
   

3. React to data changes

   When data changes on the server, let the clients know without asking. This is a form of performance improvement that frees the user from manual refresh actions (F5, pull to refresh). New challenges: (re)connection management, state reconciliation.
   

4. Control the data exchange with the server

   We can now fine-tune the data exchange with the server. Make sure to handle errors, retry on behalf of the user, sync data on the background and maintain offline caches.
   

5. Don’t break history, enhance it

   Without the browser managing URLs and history for us, new challenges emerge. Make sure not to break expectations related to scrolling. Keep your own caches for fast feedback.
   

6. Push code updates

   Pushing data without pushing code is insufficient. If your data updates automatically, so should your code. Avoid API errors and improve performance. Use stateless DOM for side-effect free repainting.
   

7. Predict behavior

   Negative latency.