Run NATS via Docker docker run -p 4222:4222 -p 8222:8222 nats -DV Set DB (Postgresql - Default user) rails db:setup With no workers (a message is sent to NATS) WEB_CONCURRENCY=0 rails s With workers (no message is sent to NATS) WEB_CONCURRENCY=2 rails s Test Watch NATS server if a command is comming from the application open https://localhost:300