15 Popular Payment Gateway Solutions:

1. PayU  
2. PayPal Payments Pro  
3. Braintree  
4. Stripe Subscriptions  
5. Skrill
6. Adyen  
7. Amazon Payments  
8. Authorize.Net  
9. BlueSnap  
10. CyberSource  
11. CardinalCommerce  
12. Payza  
13. Avangate  
14. Converge  
15. WorldPay