There are many ways to integrate Ingrid depending on your e-com platform. By installing a plugin Ingrid can be easily activated in your e-commerce.
Centra - when Ingrid plugin is activated in Centra for a merchant, Ingrid attributes are added on the Centra order.
Magento - Ingrid has a module for the e-commerce platform Magento. This means that Ingrid can be installed in the client Magento environment and then the plugin handles the conversation towards Ingrid API.
Prestashop - This module overrides the PrestaShop core class called CustomerAddressForm. And for the module to be installed correctly, please make sure the folder override/controllers and override/classes can be written to.This is needed for PrestaShop to copy the files from the module and install them in the override folder.
Jetshop - Jetshop is a full service e-commerce platform which means that they will handle installation and configuration of Ingrids checkout plugin. To activate the plugin - the site id and API key are enough.