FreeAgent
FreeAgent is UK-focused cloud accounting software for small businesses, freelancers, and accountants, providing invoicing, expense tracking, time tracking, project management, banking, payroll, and Self Assessment / VAT filing through HMRC's Making Tax Digital. The FreeAgent API is a RESTful service that exposes contacts, invoices, estimates, expenses, bills, timeslips, projects, bank accounts, bank transactions, transaction explanations, and tax timeline events for company accounts and accountancy practices. Authentication uses OAuth 2.0 (authorization code flow) and responses are available in JSON or XML.
APIs
FreeAgent REST API
RESTful API for the FreeAgent cloud accounting platform. Provides full access to invoices, estimates, contacts, bills, expenses, projects, timeslips, bank accounts, transactions...