Requires Craft 2.5+, running php 5.5.9+
Charge only supports Stripe as the payment gateway.
That's entirely by design. By limiting Charge to a single gateway, we can move quickly and support lots of advanced features that simply wouldn't be possible when covering multiple payment gateways.
Obviously Stripe won't work for every project. If you need alternative gateways, we recommend looking at Craft Commerce which has support for multiple gateways, including Stripe.