Online payment solution Spreedly vs Authorize.Net [duplicate]

They are two different layers in the payment processing stack:

1. Your merchant account, which you get from a merchant services provider or bank. Either way, it's underwritten by a bank. This is where the money you charge people goes, then they deposit it to your bank account in batches.

2. Your payment gateway, which provides an API to connect your website to a processing network for credit card transactions. Authorize.net is an example of a payment gateway. You can't use it without a merchant account, it's just a bridge between your website and the processing network the bank underwriting your account uses.

3. Subscription-as-a-service companies, like Spreedly. They are almost all new companies whose purpose is to relieve you of having to write all the code to manage recurring billing in your application. They talk to your payment gateway using your credentials the same way your website would if you wrote the code for your payment forms yourself. They don't do replace your gateway and don't work if you don't have a payment provider already.