Google Payment API - Enable an easy-to-use checkout experience for customers

Tree - Write documents in tree-like organisation with Markdown

Giftbit Payment API - Stripe for gift cards

NotePlan - Make plans inside an individual markdown note for every day in your calendar. Use it as a journal for your daily tasks and plan todos in advance. For Mac, iPhone and iPad.

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.

Markdown Here - Google Chrome, Firefox, and Thunderbird extension that lets you write email in Markdown and render...