TaxJar - TaxJar simplifies sales tax filing for eCommerce sellers.
Stripe Atlas Taxes - Help file your business taxes
Quaderno.io - Quaderno for Stripe is the simplest way to bill your customers without programming a single line of code.
neo.tax - automated R&D tax credits for startups = extra month of burn
Avalara - Cut tax compliance costs, not corners. Avalara automates tax compliance and can help improve accuracy while reducing costs.
Taxfyle - Stop doing your taxes, leave it to the professionals.