They use multiple servers for redundancy, but they are using only 5-10% capacity per [1], so they say they could run on a single server given these numbers. See

They use multiple servers for redundancy, but they are using only 5-10% capacity per [1], so they say they could run on a single server given these numbers. Seems like they've since moved to the cloud though [2]. [1] https://www.datacenterdynamics.com/en/news/stack-overflow-still-on-prem-runs-qa-platform-off-just-nine-servers/ https://www.datacenterdynamics.com/en/news/stack-overflow-st... [2] https://stackoverflow.blog/2025/08/28/moving-the-public-stack-overflow-sites-to-the-cloud-part-1/ https://stackoverflow.blog/2025/08/28/moving-the-public-stac...