Anubis is a self-hosted web firewall that stands in front of your website and makes suspicious visitors complete a lightweight challenge before their requests are allowed through. Place it between your load balancer or TLS terminator and the application it protects, with one instance guarding each service. Requests that look like scraper bots are weighed and challenged, which raises the cost of mass crawling so automated harvesting stops being free. Requests that pass are forwarded straight to your target service over TCP or a Unix domain socket, so legitimate visitors reach the real site. You define the bot policy: allowlist known good bots and crawlers you want to keep, challenge the ones you are unsure about, and turn away the rest. Challenge difficulty and weight thresholds tune how hard visitors must work, letting you balance protection against friction for real readers. The server listens on port 8923 by default and exposes Prometheus metrics on port 9090, so request and challenge rates show up in your existing monitoring. Deployment is a single Docker image or native package with minimal resource needs, and configuration arrives through environment variables plus the policy file. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.