Here's the summary of the hardware and the software that powers Healthchecks.io.
Hardware
Since 2017, Healthchecks.io runs on dedicated servers at Hetzner. The current lineup is:
HAProxy servers: 4x AX41-NVMe servers (Ryzen 3600, 6 cores)Web servers: 3x AX41-NVMe servers (Ryzen 3600, 6 core