HackerThemes - Bootstrap 4 themes and tools for web developers
Mango - The first simple online payment solution in Latin America
Bootstrap Magic - Create your Bootstrap 4.0 themes easily with magic
PayPal.Me - Request money using your own personalized URL.
Bootstrap 4 Cheat Sheet - An interactive Bootstrap 4 cheat sheet
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.