This is a PHP library for use with the Fakturoid API, an online invocing API for small businesses. API Documentation provided only in Czech, but library documentation is available in English via GitHub.
Business Profiles, online database of business registration information, provides access to its massive database via the Business Profiles API. The database contains business registrations (e.g. corporations, limited liability companies, partnerships, etc.) and additional data on shareholders, directors, public filings, and more.