Let's make this bug a meta for the various performance improvement we can do at the moment:

• API should leverage HTTP Cache (depends on HTTP API should leverage HTTP Cache (via Etag or Last-Modified-Since headers) foxbox#494);
• API should leverage HTTP Compression (depends on HTTP API should use HTTP Compression foxbox#503);
• API should provide WebSocket/EventSource endpoint to eliminate agressive polling (depends on update the web socket support foxbox#396);
• Concatenate and minify the CSS resources (depends on Concatenate and minify the CSS resources #158);
• Concatenate and minify generated scripts (depends on Concatenate and minify the generate scripts #45);
• Use minimized versions of external libs (React and React DOM);
• Optimise React for production builds](Optimise React for production builds #46);
• Somehow organize/concat/whatever SVG resources.
• Integrate web performance measuring as part of our deployment workflow and track performance regressions.