Both Puma (https://github.com/puma/puma https://github.com/puma/puma, a popular server these days) and Passenger Enterprise (paid) provide multithreaded web sup

Both Puma (https://github.com/puma/puma https://github.com/puma/puma, a popular server these days) and Passenger Enterprise (paid) provide multithreaded web support. Also on the background jobs side, Sidekiq https://sidekiq.org https://sidekiq.org is very popular.