Torollo is a hands-on backend engineering lab where the architecture you draw becomes real infrastructure, so a load balancer on the canvas is an actual Nginx container and a firewall rule you sketch is enforced by iptables. Place Ubuntu servers, PostgreSQL, MongoDB, Redis, and RabbitMQ nodes, wire them into VPCs and subnets, then watch the traffic simulator send requests through the topology you built. Guided roadmaps walk you from a single web server to a resilient three-tier application, a cache-aside Redis design, and a worker queue, grading every step against the live system instead of your intentions. Validators probe container status, SQL schemas, Redis keys, network reachability, and HTTP responses, and a failed check explains exactly what was expected versus what your containers actually did. Built-in explorers let you run SQL against Postgres, query MongoDB collections, and issue Redis commands, while browser terminals give you a shell inside any node. Roadmaps are plain JSON files you can import or author yourself, progress is tracked per step with hints and solutions, and the whole catalogue is available in English and French. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.