Catalog's shipping options differ depending on your store's Shopify plan. If you are on Shopify, activate multi-origin shipping by following the steps in the Shopify shipping profile guide. If you are using Catalog's API, the shipping-rates endpoint automatically provides the agreed-upon flat rate.
Shopify Basic vs Advanced and Plus plans
Advanced plans
If you are on Shopify Advanced or Shopify Plus, Catalog automatically adds a Catalog Delivery Profile to your App Shipping Profiles when you install the app. This allows the app to control the shipping rates of any Catalog products based on the terms agreed to in your proposal.

The Catalog Delivery Profile also gives you access to the dynamic shipping rate option. Selecting this option passes the shipping rate from the Brand's website through to your checkout.
Basic plan
If you are on the Shopify Basic plan, Catalog automatically sets up a new shipping profile with the agreed-upon flat rate for each new Brand when the proposal is accepted. If you and your Brand partner renegotiate shipping terms, Catalog updates the rate automatically.

Note: Brand's dynamic rate is available for Partners using Shopify Plus or higher. If you are using Shopify Basic, you need to upgrade your account to include carrier shipping or switch to Shopify yearly billing to gain access. Once you upgrade, contact us to get access.
How does shipping work with my free shipping threshold?
Both the Brand's products and your products count toward your free shipping threshold. This was designed with the best customer experience in mind. Brand shipping rates are still added separately for Brand products in the order. If you do not want Catalog products to count toward your site's free shipping threshold, navigate to Settings > Shipping & Orders > select Separated for your Free Shipping Contribution setting.
Note: For this feature to work, you need to download and onboard onto the Catalog for Brands app. You are required to have both apps for Catalog to correctly calculate your cart's shipping totals. This is currently a beta feature.