The Hiveage PHP SDK by Lance Pioch interacts with the API to access billing features. Installation and usage available. Hiveage aims to help freelancers in over 140 countries to facilitate invoicing processes with their clients.
Among the 25 finance-related APIs now listed on ProgrammableWeb, there are services from old and new and large and small companies. Overall, most current business and finance APIs fall into one of two categories: APIs from SaaS-based management services, and APIs that provide financial markets data.