The Stripe PHP Library by Stripe is a REST resource. The library API is designed for predictable, resource-oriented URLs and HTTP response codes to indicate API errors. Further, it is aims to support the built-in HTTP features, like HTTP authentication and HTTP verbs with off-the-shelf HTTP clients, and the support cross-origin resource sharing to allow interaction with the API from a client-side web application. The returns are in JSON, including errors.
Groupon, which calls itself a "social commerce site," is one of many online services that help consumers pool their buying power to get great deals. However, few companies can share Groupon's experience of attracting $135 million dollars from the same venture capital funds that helped grow Facebook and Zynga. To help third-party developers and affiliate members get the word out about its daily specials, Groupon has released a publicly available API.
FoodEssentials, aimed at solving food label data problems through technology, launched the LabelAPI. The API allows developers to integrate the most comprehensive, up-to-date food and drink product label database into apps and websites. Since 2004, FoodEssentials has dedicated itself to enlightening the food choice process.
Our API directory now includes 116 retail APIs. The newest is the Leaf API. The most popular, in terms of mashups, is the Shopping.com API. We list 60 Shopping.com mashups. Below you'll find some more stats from the directory, including the entire list of retail APIs.