Is there an ActiveMerchant for Sinatra?

Question

Which payment gateway library works with Sinatra if you want to add e-commerce functionality to your application?

Answer 1

ActiveMerchant works great as a standalone library as well as a Rails plugin.

It was designed for (sic) use in Ruby on Rails web applications and integrates easily as a plugin, but it also works great as a stand alone library.

gem install activemerchant