Due to the legislation of many countries, it is insufficient and not compliant to simply perform a tax calculation (or consume a tax calculation service of an external provider) just at checkout.
Rather, it is required in these countries to calculate and display the final price inclusive of taxes already on the front page, on the product page and on the shop and cart page. At this point, many platforms fail if they just consume an external tax service via API just at checkout.
A compliant marketplace has to be able to dynamically display the correct prices inclusive tax on the front page, on the product page and on all shop pages.
GT4M integrates seamlessly with your marketplace system, not only at the checkout but on any page of your marketplace.