Certain pages on the site can occasionally be slow. As of Feb 2019, the Infinite Flight API can take up to 4 - 5 seconds to provide me data. I then cache (keep a copy of) that data for about 20 seconds to both reduce load on IF’s servers and so subsequent pages load almost instantly. I hear rumors that work is underway to improve the API response time but I do not know when or if those improvements will be available.
Discrepancies between www.ifatc.org and the Infinite Flight app
Airspace rings are slightly different. The rings on the map can be off by up to a few tenths of a nautical mile. In every case I have seen, my rings are smaller than those displayed in the app. I do not believe this is fixable given limitations in the mapping library I am using.
Intercept altitudes per airspace ring are too low. The intercept altitudes shown on the approach info page page can be off by up to 300, maybe 400, feet. In every instance I have found a delta the altitudes I am showing are lower. I have put trying to fix this on hold for the forseeable future. I did quite a bit of research to try and find the source of the difference without success.
Terrain and airports can appear in the water. This issue is quite frustrating :). Airports, fixes and terrain are all correctly rendered, but, for some reason, the water layer is off by a bit. The most egregious example I am aware of is NZAA. Fixing this is also on hold since the water doesn’t really impact anything other than being visually aggravating.