This PHP Library is the official client reference for accessing the Block.io API from an application written in PHP. Block.io API offers a secure wallet and payment service for transacting the three most common cryptocurrencies (Bitcoin, Doge, & LiteCoin). The Block.io API can be used to return balances, conduct withdrawals and account maintenance, and return user IDs & addresses associated with a specific account.
The Billy's Billing API is aimed at small business entrepreneurs who have their hands full. (That description excludes no start up of course, but at certain crucial phases, it's really really hard to tear yourself away from the growth of the business to focus on...accounting. Ugh. And if you get a system that's too big for your needs to start with, it will cost you dearly in both money and time. For the small time operator, Billy's could be just the thing. Billy's goal is to handle invoices, contacts, payments, products, schedules, transactions, accounts, and more.