Trouble Accessing Cart Endpoints on a Custom Next.js Storefront

[mynoveltools]

I’m running a custom Next.js 14 app on Vercel, using Swell as my backend. I’ve used both swell-js and swell-node in other contexts without issues, but when I try to add an item to the cart (REST, not GraphQL), I get 400 errors.

I created a subdomain for my storefront under Online Store → Domains, but when I click on it, I’m redirected to https://mystoreid.apps.swellstores.com/admin/login instead of a public storefront. The docs mention a “Make Storefront Public” toggle, but I can’t find that setting in the current UI.

Question: How can I successfully make calls to the /cart endpoints in this setup so that my custom storefront can add items to the cart without 400 errors? Any help would be greatly appreciated!