Octobat - Octobat provides automated tax-compliance and accounting for digital businesses.
TaxJar - TaxJar simplifies sales tax filing for eCommerce sellers.
Symmetry - Symmetry offers software solutions for payroll witholding tax.
Thomson Reuters ONESOURCE - ONESOURCE tax software and solutions synchronize every aspect of your work and link international, country, state and local tax laws.
Avalara - Cut tax compliance costs, not corners. Avalara automates tax compliance and can help improve accuracy while reducing costs.
Taxamo - SaaS solution for the new 2015 EU VAT rules