Build it: Health Checks
An interactive sandbox where you drag real components together, connect them, and run a live traffic simulation to see where the design breaks.
Challenge: Build a load-balanced fleet that can handle <strong>90 r/s</strong> even after one server dies. Hit Play, then click the red ✕ on any server to kill it. The LB should reroute around it. The remaining servers should not overload. Survive the kill and you pass.