Like Shopify provide carrier service API to add custom shipping rates into checkout.
https://help.shopify.com/en/api/reference/shipping-and-fulfillment/carrierservice
Hi Gajendra. Apologies we couldn't reply you earlier.
Maropost Commerce can directly communicate with your shipping provider account to display live rates to customers in checkout. Follow the steps in this video to setup a direct integration with your shipping carrier.
Please refer to this video to setup shipping rates integration:
I hope this helps. Feel free to reply back with any other queries.