ESI · market orders
Sell and buy orders are fetched from the official EVE Online API for the regions and stations this instance tracks, then stored in PostgreSQL. Prices are therefore a snapshot, not a live feed - so every screen tells you when its market was last refreshed, and you always know how old the number in front of you is.
zKillboard · kills
Killmails come off the zKillboard stream and land in the database within seconds of happening. ESI publishes only an hourly aggregate, cached for an hour - which is why a gate camped ten minutes ago is invisible to it, and visible here.
ESI · universe map
Systems, gates, security status and sovereignty come from ESI as well. The map starts from the real coordinates CCP publishes, so a region has the shape you know from the game client.