OpenSalesTax vs VATCalc Calculator

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.

VATCalc Calculator determines VAT and GST for domestic and cross-border transactions, either as transactions occur or in batches. It can connect to shopping carts, ERPs, ecommerce platforms, invoicing systems, and other applications through web access and an API. Calculations draw on codified national tax laws, including the EU VAT Directive, and can include legal references and suggested adjustments. Users can map goods and services themselves, use pre-mapped HS, TARIC, and CPA codes, or apply coding assumptions with VATScript. Customer-selected exchange-rate data can be incorporated.

The product supports REST API feeds, HTTP, FTP, and other exchange formats. Listed integrations include SAP S/4HANA and ECC, SAP Public Cloud, Oracle NetSuite, Oracle JD Edwards, Odoo, and Chargebee. Transactions can flow into VAT returns through the shared VAT Filer platform, and the calculator can also be incorporated into VATCalc’s e-invoicing service. VATCalc describes the service as built on Amazon Web Services to handle transaction volumes and daily peaks without latency planning. It states that it is ISO 27001 certified. Pricing is on request, and a free trial is available.