RoadRunner

RoadRunner (https://github.com/roadrunner-server/roadrunner 8,509 ), also written in Go, keeps PHP outside the server. It runs a pool of php CLI processes and passes each request to one of them over pipes. The current release is 2025.1.15 (17 June 2026), and the PHP side comes from Composer 5,243 (spiral/roadrunner-http 4.1.0). The worker script loops on $worker->waitRequest(), which returns a PSR-7 request (Guzzle, PSR-7 and PSR-18), and replies with $worker->respond($response). In .rr.yaml, server.command names that script, and http.pool sets num_workers, max_jobs (requests before a worker is replaced) and supervisor.max_worker_memory. Because workers are processes, a fatal error kills only one, and RoadRunner starts another. Plugins add queues (AMQP, Kafka 129 , SQS 24 ), gRPC and metrics. Run rr serve under systemd 142,543 (Processes and Monitoring).