CiviCRM - A Constituent relationship management for the Civic Sector
PayPal - PayPal is the faster, safer way to pay online without sharing financial details, send and receive money or accept credit and debit cards as a seller
EspoCRM - EspoCRM is open source CRM (Customer Relationship Management) software that allows you to see, enter and evaluate all your company relationships regardless of the type.
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
Pipeliner CRM - Pipeliner CRM empowers small to medium-sized sales teams to close more deals and lower risk. Implementation and training are a breeze. Mac & Windows.
Braintree - An all-in-one solution to accept, process, and split payments in your mobile app or online - from small business to large enterprise.