Onport can become your "rate master" by sending the vendor shipping rates you create in your account to your Shopify checkout. Any rate you create can sync to your store:

For this to work, we recommend verifying your Shopify subscription plan to ensure that it allows 3rd-party apps (e.g. Onport) to manipulate your checkout.

In order to enable this setting, go to Integrations > Shopify > (select store) > Setup tab > scroll down to the bottom of the page and Enable Carrier Services:
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🔎 For more information on the vendor shipping rate types, click here.