As of July 31, 2018, new BigCommerce stores are no longer able to create Legacy API Accounts (accounts using HTTP Basic Auth) within their control panels. Existing Legacy API Accounts will continue to work until further notice, but we strongly recommend migrating to OAuth as soon as possible.

If your app or integration is still using Legacy Authentication, please follow this guide to upgrade to OAuth: https://developer.bigcommerce.com/api/#migrating-to-oauth