WebKul provides range of shipping modules from api based to matrix based . Basically There are two types of API extension exist right now API Driven Shipping Extensions - webkul provides api driven shipping extension e.g fedex , ups , usps , aramex , correios and other shipping api based module User defined shipping extension - These extension does not follow any API but here admin / vendor can set the pricing or freight calculation based on zip / pin code , weight , location and many more other parameters