Seamless tax calculations via API and Python toolkit.


The OSI Finance REST API facilitates precise tax calculations and related financial assessments. It offers a robust platform for accessing tax data, enabling accurate computation of tax liabilities and credits. With secure, user-friendly endpoints, it streamlines the management and analysis of tax information.


The osifinanceAPI is a robust Python package designed for seamless interaction with the OSI Finance REST API. It facilitates easy access to performing tax-related calculations. With osifinanceAPI, harnessing the power of OSI Finance's tools becomes effortless and efficient.


Find the right plan for your needs.


Enjoy basic access to our OSI Finance REST API at no cost, with up to 25 requests per day, ideal for getting acquainted with our tax calculation services.


At just $9.99 per month, our Premium tier provides a substantial request limit of 1,000 daily, catering to enthusiasts and small projects requiring more frequent access.


Tailored to meet the unique demands of large-scale operations and businesses, our Enterprise tier offers a customized solution. Contact us at to discuss your requirements, and we'll provide a personalized plan with a pricing and request limit for your needs.