Integrating Chargebee subscriptions and recurring billing with a Rails app

When working on a SaaS such as DynaBlogger, one obvious thing you'll need to implement at some point - well, if you want to get paid for it! - is subscriptions management with recurring billing. At a minimum, you need to use a payment gateway such as Stripe or similar if you build everything yourself. Stripe is likely the most popular gateway among developers thanks to great APIs and documentation, and is pretty easy to integrate with an existing app. It has some limits though. It's a payment gateway at its core, meaning that other features like subscriptions management - while available with Stripe Billing - are somewhat limited. Besides, if you use Stripe with your app you have a limited choice of payment methods unless you implement something like PayPal or others alongside Stripe.