Digital payments continue to become more mainstream, and that popularity continues to attract a growing segment of developers. For many top apps and an ever larger set of retailers, payments APIs are not only a core piece of infrastructure but also an enabler of innovative and new ways to approach payment transactions. This past year saw Visa release its Checkout API and SDK, while Apple launched its own mobile payment initiative with Apple Pay. Based on their reach, suitability to today’s tasks and ability to help companies more effectively integrate payments into all efforts, the following APIs stand out among the crowd.
API Documentation: https://developer.paypal.com/webapps/developer/docs/api/
PayPal is an international digital wallet-based e-commerce business allowing payments and money transfers to be made through the Internet. Its API exposes extensive functionality to developers, including invoice management, transaction processing and account management.
Not much to be said here. Everyone knows PayPal, and it has become the de facto online transaction service. The PayPal API has great documentation and is easy to implement in any program. Currently, PayPal is the best online transaction system due to its speed and almost 100% uptime, and you can’t go wrong using its service. The main downside is that it's a lot more expensive to use than competitors.
Stripe allows users to accept payments online, built with developers in mind. Stripe lets users keep track of payments, search past payments, create recurring charges and keep track of customers, and its API exposes most all of these functions over a RESTful JSON interface.
The best part about using Stripe is its ridiculously good documentation. There are clear examples for common functions and good explanations for all the functions in the API all wrapped up in a great interface. Stripe is just as expensive as PayPal, though, and that’s quite a pill to swallow considering there aren’t many differences between Stripe and PayPal once things are all set up. Nevertheless, it's a very good API and definitely easy to implement.
Dwolla is a payment network that allows any business or person to send, request and accept money. What makes Dwolla unique is that it skips the credit card middleman to increase security and lower costs, allowing anyone (or anything) connected to the Internet to move money quickly, safely and at the lowest cost possible. The RESTful API provides functionality to send, receive and request money, as well as retrieve account history and profile information via JSON and XML.
Dwolla is very similar to PayPal from a user’s perspective (which is a good thing because of PayPal’s ease of use). But the similarities end there; Dwolla doesn’t charge a percentage fee for a transaction and also removes credit card interchange fees by essentially creating a proprietary payment network like Discover, Visa and MasterCard. On the API side, Dwolla is just as easy to implement as PayPal and accepts mobile and Web transactions.
LevelUp is a one-touch mobile payments and loyalty service that powers mobile payments and rewards programs for more than 14,000 businesses and 1.5 million users on all mobile platforms. In addition to being experienced with large customer loads, LevelUp also offers analytics, processing savings and ROI-driven campaigns to improve the efficiency of a business. Its API allows developers to access all of the functionality of LevelUp in point-of-sale systems as well as accept online and mobile payments.
The LevelUp API is another very well-documented API. It is relatively easy to implement and offers a large variety of services, such as data about transactions, business location and offers, as well as mobile payment services, point-of-sale payment services, Web payment and e-commerce services, and of course loyalty and rewards integration throughout the whole process. It is definitely much more feature-rich than Stripe, Dwolla and PayPal, and is cheaper than Stripe and PayPal per transaction.