ZipBooks - ZipBooks is online accounting software for small businesses. 100% free, forever.
vatlayer API - Free VAT Validation & EU VAT Rates API
Bonsai - Bonsai is a one-stop business & finance management platform designed for creative and digital agencies. Streamline client management, track your team’s time, get paid faster and manage finances in one place.
MFLicenseCenter.com - Connect to fuel tax licenses for tax determination, return preparation, and reporting compliance.
Xero - Xero is online accounting for your small business.
TaxJar - TaxJar simplifies sales tax filing for eCommerce sellers.