OpenSalesTax review
A focused, free engine for developers who need self-managed U.S. sales-tax calculations.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
OpenSalesTax is an open-source API for calculating destination-based U.S. sales tax. It is designed for developers, merchants, and businesses that want a free, self-managed calculation engine rather than a filing or remittance service. The product supports transaction line-item calculations, ZIP-code rate lookups, jurisdiction-level breakdowns, taxability matrices, and state-specific rules. Its coverage includes U.S. states, the District of Columbia, and Puerto Rico.
The deployment model is central to OpenSalesTax. It can run through Docker Compose, PostgreSQL data dumps, or source installation, with a REST API documented through OpenAPI. Live demo and API instances provide an accessible way to review the service interface. This approach suits solo developers and small to mid-market teams that can manage their own infrastructure and want control over their tax calculation environment. The published product details describe a free offering, with no paid tiers adding separate capabilities.
OpenSalesTax stays focused on sales-tax calculation. It does not provide tax filing, remittance, legal advice, or address validation, so businesses needing a broader compliance workflow should choose a platform that includes those services. The self-hosted model also places deployment and operational responsibility with the adopting team, while documentation is the listed support channel. Choose OpenSalesTax when a free, open-source API and self-managed U.S. sales-tax calculations meet the requirement; look elsewhere when integrations, managed operations, broader tax types, or end-to-end compliance services are priorities.
OpenSalesTax pros and cons
- Where it wins
- Free and open source with self-hosted deployment
- Line-item calculations with jurisdiction-level breakdowns
- REST API, PostgreSQL dumps, and Docker Compose support
- Where it doesn't
- Covers sales tax rather than broader tax types
- Calculation only; no filing or remittance
- Docs are the listed support channel
OpenSalesTax fact sheet, pricing and score →
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update