Provider APIs use a reverse data flow — BigCommerce calls your app’s endpoints to retrieve data on behalf of a store. These are API specifications that your application must implement, not APIs you call directly.
Each provider type has its own authentication model:
Developer-configured authentication. When you register your carrier with BigCommerce, you define a carrier configuration schema. BigCommerce includes the merchant’s configuration values in each request payload. How you authenticate stores is up to your implementation.
Uses HTTP Basic Authentication. Your app establishes a connection via the Tax Provider Connection API, supplying a username and password. BigCommerce sends these credentials in the Authorization header when calling your endpoints.
For additional context, see Authentication overview.
You must be a registered single-click app in the BigCommerce Developer Portal. After registering your app and implementing the required endpoints, contact BigCommerce to receive a carrier or provider ID.