OpenSalesTax vs Vatstack

OpenSalesTax is a free, self-hosted API that calculates sales tax for US transactions using public data and per-state modules. The project says its modules cover 52 jurisdictions, while each published data dump includes all 48 jurisdictions that impose sales tax. The API calculates tax on line items and can break results down by state, county, city, or district. Documented item categories include general goods, clothing, groceries, prescription drugs, prepared food, and digital goods. Its data comes from Streamlined Sales Tax files and state Department of Revenue publications, rather than paid tax feeds. The engine can be installed from source or run with Docker; PostgreSQL is the default, with optional MariaDB support. Access defaults to open with per-IP rate limiting, or can use API keys with per-key limits and usage tracking. Release dumps reflect the SST quarterly file current at release, and the project documents loading newer data. It identifies incomplete sub-state tax stacking for Colorado home-rule cities and Louisiana parish-level collectors. The project says its calculations are not legal or tax advice and advises checking results with the relevant state Department of Revenue before remitting.

Vatstack is a VAT API for businesses selling telecommunications, broadcasting and electronic services to customers around the world. It provides rates for domestic and cross-border sales, updating them when government changes take effect. The API can calculate VAT-inclusive or VAT-exclusive prices, determine customer location from an IP address or billing address, verify VAT numbers for exemption, and adjust rates for some digital products such as ebooks. Real-time VAT and GST checks cover the 27 EU member states, Australia, Norway, Singapore, Switzerland and the United Kingdom. EU and UK checks include a consultation number, and validation records are stored in the cloud and replicated between EU data centers on AWS. Users can import a CSV for bulk checks. Vatstack compiles VAT OSS and EC Sales List reports using European Central Bank exchange rates, and integrates with Stripe to sync invoices, location evidence and tax IDs and to adjust reports after refunds. A free plan is available; paid plans start at $15/mo.