What are some alternatives?
When comparing NServiceBus and Hangfire, you can also consider the following products
IBM App Connect - IBM App Connect is the all-in-one integration tool for connecting apps, integrating data, building APIs and acting on events
RabbitMQ - RabbitMQ is an open source message broker software.
Apache Camel - Apache Camel is a versatile open-source integration framework based on known enterprise integration patterns.
Sidekiq - Sidekiq is a simple, efficient framework for background job processing in Ruby
Software AG webMethods - Software AG’s webMethods enables you to quickly integrate systems, partners, data, devices and SaaS applications
Resque - Resque is a Redis-backed Ruby library for creating background jobs, placing them on multiple queues, and processing them later.